This essay is a study in the demographics and geography for fanfiction writers who want to envision what America might be like in the wizarding world of Harry Potter. It is certainly not canon; it rarely rises above the level of rank speculation! It does, however, seek to address basic background issues that may be usefully explored by those who would like write Harry Potter fanfiction set in the United States.
Let's begin by estimating that the number of wizard births in the world is roughly 1 per 10,000 Muggle births. This works out to about 6,600 human wizards in the United Kingdom (6,184) and the Republic of Ireland (445) and about 31,300 in the US and its territories (Puerto Rico, US Virgin Islands, etc.). J. K. Rowling has made statements in interviews that would suggest a much lower population level. We shall see, however, that it is preferable to judge by what Rowling shows us rather than what she tells us when it comes to numbers. If anyone prefers to work with a ratio closer to 1:20,000, they should feel free to adjust my math accordingly.
To compare British and American population data correctly, we must use figures from the time period portrayed in the books. These figures can then be compared to earlier or later time periods either in Britain or in other parts of the world. Harry Potter's first year at Hogwarts was 1991. In that year, the population of the U. K. was approximately 57.8 million and of Ireland was approximately 3.5 million. With the 1:10,000 ratio I'm proposing, this would give us an approximate wizarding population of 6,131: 5,781 in the U. K. and 350 in the Republic of Ireland. Let's see how we can use these figures to come to some general conclusions about the demographics of wizarding Britain, and then apply these conclusions to the American situation.
I. Overall Population
The Wizarding Population of North America—and thus the enrollment in its various wizarding schools—is calculated based on the following assumptions:
A. Baseline. There is 1 wizard born for every 10,000 Muggle births. I assume this ratio holds, with slight variation, across all ethnic and geographic lines. No group of humans is intrinsically more or less magical than any other. To my knowledge Rowling has never stated that this is the case, but it seems to conform to the overall ethos of her books.
B. Modifiers. The 1:10,000 ratio gives us a good first step in estimating the wizarding population of any country, region, state, or city. It is possible, however, to fine-tune this number at the state level in the US by considering factors that might drive the wizarding population slightly above or below this benchmark.
For instance, writers may wish to modify this baseline to account for the general level cultural diversity or eccentricity of a state (see Section II). Although these factors would play a larger role at the city level, writers might want to include them at the state level as well. In no case, however, should the accumulated modifiers result in a total US wizarding population higher or lower than whatever national baseline the writer accepts.
In the interests of preserving wizarding secrecy, one might also assume that many wizards would likely live in out-of-the-way places—the bayous of Louisiana, the hills and hollers of Appalachia, or the desert Southwest, for example. Therefore, one might apply a modifier that favors states with low population density over those with high population density.
Another factor having to do with wizarding secrecy involves home-school regulations. Apart from Muggle-borns, most wizarding children are not enrolled in Muggle elementary schools for fear of violating wizarding secrecy. While it is likely the state possesses no record of the existence of many if not most wizarding children, issues of truancy and the threat of state involvement probably exert at least some influence on where wizarding families choose to live. I therefore propose that the relative "friendliness" or "hostility" of state home-schooling regulations should be considered in the geographic distribution of American wizards.
Based on these assumptions, here are my estimates for the wizarding population of all fifty states and the District of Columbia:
(1) California (3,571)
(2) Texas (2,623)
(3) Florida (1,880)
(4) New York (1,841)
(5) Illinois (1,338)
(6) Pennsylvania (1,210)
(7) Ohio (1,154)
(8) Michigan (1,018)
(9) Georgia (969)
(10) North Carolina (954)
(11) New Jersey (905)
(12) Virginia (800)
(13) Washington (672)
(14) Indiana (667)
(15) Arizona (658)
(16) Tennessee (635)
(17) Massachusetts (622)
(18) Missouri (617)
(19) Wisconsin (580)
(20) Maryland (571)
(21) Minnesota (530)
(22) Colorado (508)
(23) Alabama (488)
(24) South Carolina (463)
(25) Louisiana (458)
(26) Kentucky (443)
(27) Oregon (387)
(28) Oklahoma (386)
(29) Connecticut (368)
(30) Mississippi (303)
(31) Iowa (302)
(32) Kansas (294)
(33) Arkansas (292)
(34) Utah (282)
(35) Nevada (278)
(36) New Mexico (212)
(37) Nebraska (187)
(38) West Virginia (185)
(39) Idaho (165)
(40) Hawaii (136)
(41) Maine (133)
(42) New Hampshire (131)
(43) Rhode Island (102)
(44) Montana (103)
(45) Delaware (92)
(46) South Dakota (82)
(47) Alaska (75)
(48) North Dakota (64)
(49) Washington DC (60)
(50) Vermont (60)
(51) Wyoming (58)
C. Race/Ethnicity. It is possible to find state-by-state breakdowns by racial or ethnic group online with a search for "distribution by race and ethnicity." The most basic data are probably enough to get most writers started. Some will want to research further if they are interested in particular groups (according to country of origin, etc.). In general, wizards should conform to the same general parameters as the Muggle population.
It is conceivable that Native American wizards were better able to withstand the diseases and violence inflicted by Europeans in the colonial era and beyond. If so, a writer might be justified in slightly augmenting the percentage of Native Americans in the wizarding population.
Similarly, one might suppose that African wizards were better equipped to avoid becoming enslaved and transported to the Americas in the first place. If so, the number of African American wizards might be somewhat lower than expected.
Both of these possible divergences from Muggle demographics raise unfortunate implications a writer might prefer to avoid (Why are there so many Native American wizards? Why are there so few Black wizards?). If addressed at all, these issues should be handled with great care so as not to offend one's readers.
II. Population Centers
Britain has only one major concentration of witches and wizards, Greater London, which is also home to about one-fifth the Muggle population of Great Britain and Ireland. London is home to the seat of the wizarding government, the premiere (only?) wizarding hospital in the country, and Diagon Alley, the main mercantile center. It is the city from which all Hogwarts students board the Hogwarts Express at the beginning of every school year. In America, the population is more evenly dispersed, although certain settlement patterns will be discernible. Calculating the likely wizard population of a given area involves adjusting the basic 1:10,000 ratio based on a number of assumptions:
A. Wizards may be better represented in older cities than newer ones. For all its inherent strangeness, wizarding culture gives the impression of being quite traditional. The oldest American cities might have as many as 150% of the population one would expect based on Muggle population figures alone.
B. Wizards probably prefer to live in cities with obvious cultural diversity. Cities that represent a crossroads of various nationalities, lifestyles, religious traditions, etc. afford wizards greater opportunity to blend in with their Muggle neighbors without drawing undue attention.
C. Finally, wizards tend to bask in—and generate—a level of overall weirdness and eccentricity. A city's "weirdness" factor might be quantified by taking into account:
• The overall "eccentricity" of the Muggle population. Everything else being equal, New York and San Francisco are more likely to attract large wizarding populations than Des Moines, Iowa or Terre Haute, Indiana. Rita Arabella Black plays with this factor by setting a scene in her "The Adventures of the Dragon Keeper" in Austin, Texas, where the informal city motto is "Keep Austin Weird." (Do an Internet search for the Daily Beast website article titled "America's Craziest Cities")
• A reputation for being "haunted." This may indicate a larger than normal presence of wizards, ghosts, and other magical Beings. The most "haunted" cities in America (New Orleans LA, Savannah GA, etc.) almost surely have a greater than average proportion of wizards and witches. (Do an Internet search for the article "Top 10 Most Haunted Cities in the U.S.")
Statewide figures should carry more authority than figures for urban centers, however. Writers should be careful to keep their "favorite" wizarding cities from growing larger than the states in which they are located! Even if this involves some fudging of the modifiers, it seems better to arrive at plausible state populations and then work toward the fine detail in the cities, suburbs, and rural areas.
Based on these assumptions, here are my estimates for the top 20 wizarding population centers in America:
(1) New York Metro Area (2,035)
(2) Greater Los Angeles (1,752)
(3) Chicago (1,184)
(4) San Francisco Bay Area (715)
(5) Philadelphia (590)
(6) Washington DC (564)
(7) Houston TX (488)
(8) Miami–Ft. Lauderdale FL (468)
(9) Dallas–Ft. Worth TX (462)
(10) Detroit MI (435)
(11) Phoenix AZ (343)
(12) Atlanta GA (333)
(13) Boston MA (292)
(14) New Orleans LA (280)
(15) San Diego CA (253)
(16) St. Louis MO (245)
(17) Tampa–St. Petersburg FL (208)
(18) Riverside–San Bernardino CA (203)
(19) Portland OR–Vancouver WA (178)
(20) Austin TX (170)
The New York metropolitan statistical area (MSA) includes counties in New York, New Jersey, Connecticut, and Pennsylvania. That is why the figure for the population of "New York City" in this list is larger than that of "New York State" in Section I. By my calculations, the population of the actual City of New York is around 1,300 wizards. The Chicago, Philadelphia, Washington DC, and Portland–Vancouver MSAs also encompass counties in two or more states. For the largest urban areas, it may be helpful to break them down into constituent parts (e.g., counties) to get a more accurate overall sense of what the wizarding population might be like and where precisely it may be located.
The largest urban centers would likely contain a discrete wizarding neighborhood or two (such as Diagon Alley in London). In many other cities, the wizarding population might be more dispersed. For example, the Snapes lived in a good-sized mill town, but there is no real indication that Spinner's End was anything other than a Muggle neighborhood that happened to be home to a family of wizards.
I would like to note that Inverarity seems to have done his homework on this front in his "Alexandra Quick" stories. He describes both Chicago and San Francisco as large wizard population centers, each with at least one discrete wizarding neighborhood, while the fictitious city of "New Roanoke" is a comparatively small all-wizarding community in coastal Virginia.
III. Other Communities
Because of the need for secrecy, wizards on both sides of the Atlantic often gravitate toward remote, out-of-the-way locations where there is less chance that Muggles will discover their true nature. These communities may be of three types.
A. The first is the all-wizarding settlement (AWS). In 1990s, Hogsmeade is the only all-wizarding settlement in Britain. It is unknown if other all-wizarding settlements existed in the past. Based on the history Rowling has provided, however, I tend to think the existence of exclusively wizarding communities is something of an innovation. Originally, wizards and Muggles lived openly side-by-side, and it is only in recent centuries that the two societies have definitively grown apart. The best candidates for all-wizarding communities in America are probably, like Hogsmeade, small villages adjacent to some important wizarding institution: a school, a dragon preserve, or what have you.
An average medieval village might not have had more than 100 residents. This is probably a good benchmark for AWSs as well. It seems likely the largest American AWSs might have no more than 100–200 residents. Hogsmeade might conceivably be somewhat larger than this, but as the only AWS in Britain—and, one that has been in existence since the tenth century—this can certainly be allowed.
B. The second type of community might be a called a "mixed" wizarding settlement (MWS). In this kind of settlement, a number of wizard families live in close proximity to one another as an enclave within a larger Muggle community.
In Britain, Ottery St. Catchpole is an excellent example of a "mixed" settlement. The Weasleys, Lovegoods, Fawcetts and (at some distance) the Diggories live in close proximity to one another, but there is also a larger Muggle village nearby. The same might be said of Godric's Hollow, Upper Flagley, Tinworth, and no doubt other locations as well. All of these places seem well away from major population centers.
It seems highly unlikely that more than 30–50 wizards would be attached to a larger Muggle community in this way. If Ottery St. Catchpole and Godric's Hollow are somewhere near the average, the numbers might well be quite a bit smaller.
In Rowling's books, all of the named MWSs are fictional, although they bear a resemblance to actual towns and villages such as one might expect to see in the regions described.
C. Finally, it is possible that some wizarding families are unique to their communities. We might call these isolated wizarding settlements (IWS). They preserve the secret of their true nature and have limited contact with other wizards except through school, work, family reunions, etc. The Gaunts seem to have been the only wizarding family in Little Hangleton. And as far as we know, the Malfoys are the only wizarding family in their particular (unnamed) community in Wiltshire.
Once again, we can make some general assumptions that will at least get us in the ballpark as to how the wizarding population is distributed:
(1) Begin with the approximate statewide population as calculated in Section I.
(2) For every major urban center in the state, calculate the number of wizards likely to live there, adjusting the figure up or down as seems appropriate to account for each city's age, diversity, and overall weirdness, as described in Section II.
(3) The remainder of the state's wizarding population will be found in rural areas. How these are distributed among AWSs, MWSs, and IWSs will vary from state to state. If there is no compelling reason for a state to have an AWS, it probably shouldn't have one. If it does have one, its population should probably be between 50-150 individuals (up to 200 or so for the very largest such communities).
As a rule of thumb, perhaps 80% of the remaining wizarding population will live in MWSs with a size of perhaps 10–30 individuals (or possibly as many as 50), with the remainder in IWSs consisting of no more than 1–6 (no more than 10) individuals.
III. School-age Population
Since the population of the US is roughly five times that of Great Britain and Ireland, it is possible that the US hosts five Hogwarts-sized schools of magic, or even a smaller number of schools that would dwarf Hogwarts. It seems far more likely, however, that American schools would be for the most part smaller and more numerous. The assumptions stated in Section I can be used to calculate the likely enrollment for any American wizarding school once one determines the geographic distribution of its students. For example, a school that only serves students from North and South Dakota will be far smaller than one that serves even half the available students from California or Texas.
Rowling's comments in interviews notwithstanding, a good case can be made that Hogwarts has an enrollment of around 250–300 students. This is almost always the size of school Rowling shows us whenever she describes class sizes, dorm facilities, faculty-to-student ratios, etc. The 1:10,000 birth ratio I'm proposing, however, means that Hogwarts should have a good deal more students than that. Where are the other children?
To account for the discrepancy, I propose that not every young British wizard attends Hogwarts. Rowling herself implies this is the case, of course. First, attendance at Hogwarts was only made compulsory under Lord Voldemort in Harry Potter's seventh year. Hogwarts may well be the only British wizarding school of any appreciable size, but if attendance was not compulsory it was clearly not the only option wizarding families were willing to consider.
What were these other options? Some children might be sent to school overseas, perhaps to Beauxbatons or Durmstrang (an option the Malfoys considered for their son, Draco). Others might be home-schooled. A tiny number might begin at Hogwarts but drop out (like Stan Shunpike?), be pulled out by their parents (like Eloise Midgen), or be expelled (like Rubeus Hagrid). Furthermore, since seventeen is the age of majority under wizarding law, some students may simply opt not to return for their seventh year. Finally, I'm unwilling to dismiss out of hand the possibility of a separate, much smaller school serving young witches and wizards in the Republic of Ireland.
How many children are available to attend American wizarding schools? To discover this number, we need to calculate the size of the seven-year age cohort of wizarding children aged 11–17 as a percentage of the overall population. If American wizard life expectancy is the same as that of Muggles (about 79 years), then approximately 9% of the wizarding population is of school age. The higher the proposed wizard life expectancy, the lower the percentage, but I would think 7% (wizard life expectancy of 100 years) has to be about the lowest possible. Let's assume 8% is the correct figure. As I suggested above, however—and as must be true of Britain at the population level I'm proposing—not everyone attends a large residential school similar to Hogwarts. In keeping with the great diversity of the American population, local wizarding authorities would likely create a number of options for their constituents.
For example, in addition to residential schools, there may also be a small number of day schools located in the largest urban centers. Furthermore, some wizards might opt to home-school their children. Those with strong ties to a particular magical heritage or tradition (e.g., Hispanic, Native American, Far Eastern, etc.) might even create some sort of "home-school co-operative" at the state or regional level.
As but one example of how this might play out, in my "Malkin Academy" stories I supposed that along the East Coast there are three "old-line" schools serving states that were formerly the New England, Middle, and Southern Colonies (Florida is large enough to have its own small school if it so chooses). Another school might serve the Southwest. Texas almost certainly has its own school—and anyone from Texas will be happy to explain why! Another two to four schools might serve the Pacific Northwest, the Rockies, the Great Plains, and the Midwest. Louisiana, with its mixed French-Spanish heritage, is a perfect candidate to have its own school with distinct educational traditions.
These factors suggest something like the following breakdown:
A. Seven-twelfths of all American wizarding children, (8% x 7/12 =) ~4.667% of the total wizarding population, attend a large residential school. The remainder are educated under different arrangements, usually home-schooling. If the same proportion of young British wizards attended Hogwarts, it would give a total 1991 enrollment of 286 students, approximately 72 in each of 4 houses or about 41 in each year—which is essentially what Rowling depicts for the early- to mid-1990s.
B. In the largest urban areas (see Section II), there may be a wizarding day school available. Where available, such a school might take in three-fifths of the remaining school-age population, or approximately (8% x 3/12 =) 2.000% of the total. Such a school would probably only be able to operate if there were at least 10–20 available students—meaning a minimum population of 500 or so wizards at a 1:10,000 birth rate.
C. All remaining wizarding children—approximately (8% x 2/12 =) 1.333% of the total in the largest cities or (8% x 5/12 =) 3.333% elsewhere—are either home-schooled, educated overseas, or receive some other sort of non-traditional magical education.
This number would also include those who dropped out or were expelled, seventeen-year-olds who choose not to attend their final year, Muggle-borns forbidden to attend any school of magic, and perhaps even a tiny minority of Muggle-borns who slip through the system and whose magical gifts remain undetected.
For example, let us consider the New York metropolitan area. I calculate a total of 2,035 wizards in this sprawling metropolis. Given this number, we might estimate:
• About 95 students (4.666% of the total) attend the appropriate residential wizarding school.
• About 41 students (2.000% of the total) attend a day school probably located in one of the five Boroughs of New York.
• The remainder, about 27 students (1.333% of the total), are home-schooled, drop-outs, educated overseas, etc.
IV. Non-Human Population
What about other magical Beings who play a role in wizarding society? Is there any way to estimate the number of goblins, elves, veelas, hags, dwarfs, and other humanoid citizens of wizarding America? The short answer is "Probably not." But let's see if we can propose some plausible numbers, anyway.
A. House Elves. We can probably come closest to calculating the right number of house elves, though even here we are forced to fudge and speculate. Our first task is to decide how many wizarding families have house elves at all. Rowling depicts house elves serving only wealthy and influential families, so perhaps we should look only at the top 5% of the wizarding socio-economic ladder. In 1991, this would mean the top 307 individuals. Given an average British family size of 3.8 (mother, father, and 1.8 children), this gives us approximately 81 families with house elves.
New elves have to come from somewhere. Since Winky's mother and grandmother served the Crouches and Kreacher's ancestors served the Black family, it is a given that at one time families of elves lived at the Crouch mansion and at Number 12 Grimmauld Place. But how large is an average family of house elves? Unless we assume the species is headed for extinction, we must propose that each generation of elves produces a number of offspring necessary to maintain the current population level. And unless elf biology works radically different than human biology, this means two children per couple.
What we don't know is how many of these elf families are intact. Are elf families split up to divide the "inheritance" among a witch or wizard's heirs? If a family has more elves than it needs, does it "donate" the surplus to Hogwarts? Furthermore, how do house elves find mates in the first place?
All that can be said is that in the books most house elves outside of Hogwarts seem to live in isolation from others of their kind. The Malfoys, the Crouches, and Sirius Black are all served by a single elf. Let's suppose, however, that on average two or three house elves serve a given wealthy British wizarding family (and thus almost all of them live in what might be called "broken homes"). This would give us a total house elf population of around 162–243 individuals (2 or 3 in each of 81 households), to which we can now add the number that work at Hogwarts.
According to The Goblet of Fire (ch. 12), there are "over a hundred" elves working at Hogwarts. This seems more than would be strictly necessary for the upkeep of the school, but it is possible—even likely—that elves thrive like nowhere else under the compassionate conditions to be found there. Let's set this number arbitrarily at 120.
Combined with the 162–243 assumed to serve wealthy wizard families, we can very tentatively propose that the total elf population of the U. K. and Ireland is in the range of 282–363. This works out to about one elf for every 17–22 human wizards.
B. Goblins. It is unclear how many goblins work at Gringotts. It is even less clear how many goblins do not work at Gringotts! Goblins, however, are far more likely than house elves to be seen in groups on the pages of Rowling's books. There have been enough of them in past centuries to incite numerous rebellions against human wizarding society. We can assume that there are at least as many goblins as elves, and perhaps quite a bit more. I propose goblins might be two to three times as common as elves, and thus the British goblin population is about one for every 5.7–11 human wizards.
C. Leprechauns. "Thousands" of leprechauns served as mascots for the Irish Quidditch team in 1994. Leprechauns are almost certainly limited to Ireland, however, and their role in wizaring society is negligible. There doesn't seem to be any compelling reason to try to calculate their numbers, although American cities or regions with a large Irish presence may well be home to great numbers of them. For what it's worth, if there are indeed "thousands" of them in Ireland, they outnumber the Irish human wizarding population by at least 6 to 1.
D. Other Beings. Other magical Beings do not seem terribly common in wizarding Britain. Other than the dozen dwarfs Guilderoy Lockhart hired to deliver Valentines during Harry Potter's second year at Hogwarts and the security trolls hired to guard Gryffindor Tower in his third year, they almost always appear in isolation. Dwarfs, hags, vampires, and others apparently exist in much smaller numbers overall—or are so reclusive that their influence in the greater wizarding society is negligible.
If we discount for a moment Ireland's leprechauns, perhaps the total of all other Beings combined reaches the number estimated for elves, or about one for every 17–22 human wizards.
E. Totals for the U. K. and Ireland. Based on the above considerations, I might hazard a wild guess that the total 1991 non-leprechaun, non-human population of the U. K. and Ireland is 1,138–1,815 or roughly one for every 3.4–5.4 human wizards. That number can be further broken down as follows:
• 564–1089 are goblins
• 282–363 are house elves
• 282–363 are all others (hags, werewolves, etc.)
E. Totals for America. The non-human wizarding population of America largely depends on how the writer imagines it. Although a ratio of 1 non-human for every 4–5 human wizards is probably on target, there are a multitude of factors to consider. How many early colonists brought house elves over with them? How many goblins does it take to run the American branch—or, more likely, branches—of Gringotts Wizarding Bank?
Far more intriguingly, what new sorts of non-human Beings did European wizards encounter in the Americas, and how are they integrated into wizarding society? Native Americans have legends about creatures that might be local equivalents of elves, goblins, and several other categories of Beings. Unless these populations were entirely wiped out, they should be included in America's wizarding society in one way or another.
Let us now apply these assumptions about population to Quodpot, the most popular wizarding sport in America. Population estimates affect Quodpot in at least two ways: calculating how many teams are likely to exist and calculating how many fans are likely to attend games.
A. Quodpot Teams. According to Quidditch through the Ages, there are thirteen professional Quidditch teams in the U. K. and Ireland. Since there are about five times more people in the US, one might assume there are therefore about 65 professional Quodpot teams in America. I suspect the number should be somewhat less than this, however.
First, we must remember that Quidditch also has a following in America alongside Quodpot, although Quodpot is more popular. Quidditch and Quodpot teams compete for the same fan base in America in a way that is not seen in Britain. Second, I simply think Rowling has underestimated how large a fan base must be to field a professional sports franchise. America probably supports no more than about 30–35 professional Quodpot teams, along with somewhat fewer Quidditch teams (I would suggest maybe half as many Quidditch as Quodpot teams).
Where might these teams be located? I think a strong clue might be found by looking at the most populated cities and states in the country. If we look at the top 10 states and the top 25 cities, we may have a decent idea of where these Quodpot teams have their headquarters. American readers will be able to name professional Muggle sports franchises associated with all of these places. In the wizarding world, some of their magical counterparts may be smaller, semi-professional teams, and there may even be other teams of this type. Also, a team may actually be headquartered in a suburban or outlying area. The Dallas Cowboys play in Irving, Texas; the Detroit Pistons in Auburn Hills, Michigan.
Furthermore, just as American Major League Baseball includes teams from Canada, it would not be surprising if the American Quodpot league included a handful of Canadian and even Mexican teams.
B. Quodpot Fans. How many people are likely to attend a professional Quodpot game? According to chapters 6 and 8 of The Goblet of Fire, about 100,000 fans attended the 1994 Quidditch World Cup (QWC). The world population in that year was 5.662 billion people, giving an estimated global wizarding population of 566,200. Even with my very generous 1:10,000 birth ratio, this means that over one-sixth of the entire global wizarding population attended the 1994 QWC!
As absurd as this seems, it may not be entirely impossible. Since the game was obviously not televised and since transportation would not be as great a concern for wizards as it is for Muggles, it is conceivable that a larger percentage of wizards would make the effort to attend an important Quidditch match than Muggles would a football game or other sporting event in their world. Furthermore, Quidditch seems to hold a virtual monopoly on wizard sport, at least in Europe. It is the only game in town, and it has plenty of rabid fans. Finally, the QWC is only played every four years. It may well be something people plan and save for months if not years ahead of time, much as some avid fans plan and save to attend the FIFA World Cup.
Still, one wizard out of every six worldwide attending a single event of any kind stretches my willing suspension of disbelief up to and beyond the breaking point. I can't help but wonder, therefore, if other factors might serve to bring this number of 100,000 down to something even slightly more realistic.
One canon-compliant possibility is that the 100,000 figure includes both human and non-human attendees. It is unlikely that many house elves other than Winky attended the 1994 QWC, but there were certainly "over a hundred" veelas and "thousands" of leprechauns. At least one group of goblins attended, and probably many more. Might these have been included in the total figure Mr. Weasley told Harry?
Second, I'm strongly disposed toward chalking up the 100,000 figure as a mathematical infelicity on Rowling's part, whether or not a credible in-story work-around is possible. If we want to be generous, we might suggest that Mr. Weasley was simply misinformed about the projected attendance of the QWC, and his report to Harry, while given in sincerity, was simply erroneous.
Overall, I am more comfortable with an actual attendance figure of no more than 1/8 to 1/10 of the global human wizarding population, or between 60,000–75,000 attendees. Even this is probably far too many. It is a much greater percentage than anything comparable in Muggle sports attendance.
For purposes of comparison, consider the following statistics:
(1) The record attendance for a final game in the FIFA World Cup is 114,000 for a game between Argentina and West Germany, played in Mexico on 29 June 1986. There were 4.932 billion people on earth in that year, meaning this match was attended by approximately 1/43,000 of the world's population.
For a decisive (non-final) match, the record is nearly 200,000 (Uruguay vs. Brazil, played in Brazil on 16 July 1950). This represents 1/13,000 of the 2.556 billion people alive in 1950. Alternately, since this game involved teams from neighboring countries, we might look at the estimated population of South America. In 1950, that number was about 112 million. This means 1/560 of all South Americans attended this match.
(2) The 1996 Summer Olympic Games in Atlanta, Georgia, drew an estimated 2 million fans. At that time, there were 5.822 billion people on the planet, so this attendance represented a bit more than 1/3,000 of the total human population.
(3) The largest stadium in the world is Rungnado May Day Stadium in Pyongyang, North Korea, with estimated seating for 150,000. In a country with 23.9 million citizens, this amounts to about 1/160 of the total population.
(4) The largest sporting venue in the world is Indianapolis Speedway in Indianapolis, Indiana, with a capacity of 257,000. This number is approximately 1/1,200 the population of the United States and 1/25 the population of the state of Indiana.
(5) The largest stadium in the United States is Michigan Stadium in Ann Arbor, with a seating capacity of 108,000. This is about 1/2,900 the population of the United States and 1/90 the population of the state of Michigan.
A "realistic" figure of perhaps 1/2,000 of the global wizarding population would mean that only about 300 witches and wizards attended the 1994 QWC. Such a figure utterly fails at the storytelling level—Rowling wanted to impress Harry (and us) with the vastness and diversity of the wizarding world. I fear, however, that she erred too far in the opposite direction and gave us a QWC attendance figure that is simply unsupportable.
An adjusted 1994 QWC human attendance of 1/8 to 1/10 of the world wizarding population is still at least ten times what might be expected based on comparable Muggle data—and probably several hundred times. Given the factors of ease of travel, lack of television, and a virtual Quidditch monopoly on sports entertainment, we can probably let this number stand, however.
Following this logic, then, let's assume that a national championship Quodpot game would similarly draw 1/8 to 1/10 of the American wizarding population if it were only held every four years. Working from 2010 census figures, we would be talking about roughly 3,100–3,900 fans. If one prefers the original 1/6 figure (and this might be justified if a Canadian or Mexican team were in the finals—but I'm highly skeptical), the number would go up to just over 5,200.
What if the Quodpot championship is held every year? Are this many people likely to attend? I doubt it. For a yearly championship, however, the total attendance would likely be somewhat higher than what we get by simply dividing by four, i.e., roughly 775–975 (maximum, about 1,300). Some Americans attend the Super Bowl, a World Series game, or the NCAA Final Four every year, and some have done so for decades. Somewhere between 1,000–2,000 fans therefore doesn't seem unreasonable for an annual championship game, given the assumptions with which we started.
Of course, games where the stakes are lower would naturally not bring in as many fans. In most American venues, ticket-takers would probably be thrilled to have as many as 750 or so in attendance, and for some games between weaker or less established teams even that may be far too high a number.