Surveys find that about one-quarter of the United States population, or between 75 and 80 million people, follow college football regularly. But which teams do they align themselves with?

This question is not easy to answer, but we’re going to make an effort to resolve it, and then use the results to shine a light on college football’s increasingly complicated realignment picture.

The premise of the study is this: take the 210 television media markets in the United States, figure out how many college football fans they have, and then allocate them between the 120 current Football Bowl Subdivision programs.

The first part of the problem isn’t as easy as you might think, because enthusiasm for college football varies radically across different parts of the country — far more than for other sports.

One way to estimate the regional variances is to look at Google search traffic. For instance, according to Google Insights for Search, the term “college football” is searched for about 5 times as often in Birmingham, Alabama as it is in New York City, relative to overall search traffic.

In other words, on a per-capita basis, there are probably about 5 times as many football fans in Birmingham as there are in New York. So although the New York media market is about 10 times larger, it has fewer than twice as many college football fans as Birmingham.



New York, because of its very large population, is still the largest market in the country for college football. But only barely: Atlanta has nearly as many college football fans, for instance, based on an extrapolation from the Google data, while Dallas (and even Birmingham) aren’t far behind.

The second part of the challenge is dividing the fans in each market between the 120 F.B.S. schools.

One effort to study this is through something called the CommonCensus Sports Map Project, an online survey that asked fans to pick which college football team they’re most loyal to as well as to enter their geographic coordinates. After having collected more than 30,000 responses over the past several years, this has allowed the CommonCensus folks to divide the country up between the different college teams into what looks like a Jackson Pollock painting.

The CommonCensus data also allows you to zoom in on any particular region, and develop an estimate of how fan loyalties are divided in any particular part of the country.

Because this survey is not quite scientific — although the CommonCensus curators have made some effort to screen out ‘spam’ responses — I’ve adjusted the results based on a comparison to the college football revenues received by each team, according to disclosure data filed with the federal government. Teams that had a significantly higher- or lower-than-expected number of fans in the CommonCensus results in comparison to their revenues had their results adjusted accordingly. (The team affected most profoundly by this is Arkansas State, which was rather popular in the CommonCensus poll but which brings in few revenues from college football and doesn’t usually sell out its small stadium.)

There are a few other kinks to work out. The CommonCensus poll did not include Western Kentucky, a relatively new F.B.S. program, as one of its choices. (I assigned it half of its home market of Bowling Green, Ky., as well as small portions of Louisville and Lexington.) And it doesn’t provide data for Hawaii and Alaska (I gave most of the former to the University of Hawaii while ignoring the latter — sorry Alaskan football fans.)

Nevertheless, this allows us to develop an estimate of how many fans there are for each team — and where they are located.

The most popular team in New York, for instance, is Rutgers. They have about 600,000 fans in New York City. That isn’t bad, but it represents only about 20 percent of college football fans in New York (in addition to some competing teams like Syracuse, many New Yorkers are transplants and bring their football loyalties with them). It also represents only about 3 percent of New York’s overall population.

The contrast might be something like Omaha, Neb. It’s a much smaller market — but it’s far more football-avid than New York, according to the Google data. And it is dominated by one team, Nebraska, which has in excess of a 70 percent market share. Thus, Nebraska has about two-thirds as many football fans in Omaha as Rutgers does in New York, even though the market is about 18 times smaller.

If you add up these results across all 210 markets, the three most popular teams are the three that also usually have the largest home attendance: Ohio State, Michigan, and Penn State. (Ohio State is ranked first in the country with about 3.1 million fans.)

These teams get to have their cake and eat it too, dominating a series of smaller markets while also scoring points in some relatively large ones like Philadelphia and Detroit — and having large enough alumni bases that they even have some reach in places like New York.

Following these three teams are Notre Dame — and then six southern schools, led by Texas and Texas A&M. Two teams from Alabama manage to make the top ten because the state’s football avidity is more than enough to make up for its mid-sized population.

This approach isn’t going to be perfect — unless you were willing to spend literally hundreds of thousands of dollars on a scientific survey of college football fans, you’re going to have to resort to some educated guesses.

Nevertheless, it ought to provide us with some insight. The S.E.C.’s interest in Texas A&M becomes easier to understand once you recognize that the Aggies have among the largest fan bases in the country. The fact that Notre Dame’s fans are dispersed throughout the country explains why they’ve been loathe to join a conference. And that the West Coast is less enthusiastic about football than other parts of the country, making the Pacific-12 a harder sale to the television networks, explains why the conference is going to great lengths to expand into football-crazy states like Texas.

Let’s review the results on a conference-by-conference basis with an eye toward realignment. Conferences are listed in order of their aggregate number of fans based on their current configurations.

Big Ten

The Big Ten can afford to be picky. Ohio State, Michigan and Penn State are the three most popular college football teams in the country, according to our study. Seven Big Ten teams, including new addition Nebraska, rank in the top 20 nationally. And all but one Big Ten school is in the top 50, the lone exception being Northwestern, which has the Chicago market and strong academics going for it.

The only plausible additions that would allow the Big Ten to improve upon its average of about 1.5 million fans per team are Notre Dame (2.3 million fans) and Texas (also 2.3 million). But good luck adding those schools.

Missouri, with 1.1 million fans — about as many as Nebraska — wouldn’t be far from the league average. Kansas (0.8 million) would be more of a stretch from a football standpoint but could bring in substantial college basketball revenues.

There’s also long been talk of the Big Ten expanding into the Notheast. But Rutgers (0.9 million fans) and Connecticut (0.6 million) are only middling targets on their own merits because of the relatively low enthusiasm for college football in the region (the same would have gone for Syracuse or Pittsburgh, which just decided to join the A.C.C.).

Then again, we estimate that there are about 0.6 fans of the current Big Ten schools in the New York City market alone, so a lot of people might tune in hoping to see one of these schools lose.

One outside-the-box target: Virginia Tech. In addition to its natural (and quite avid) fan base in western Virginia, it also has some reach into Washington, D.C. and other relatively populous markets — enough for it to rank 13th in the country with 1.3 million fans.

S.E.C.

The S.E.C. has few large media markets — Atlanta’s Georgia Tech is in the A.C.C., as is the University of Miami. But if it adds Texas A&M, it will be up to 15.6 million fans total, just barely behind the Big Ten (17.5 million). The enthusiasm for college football in the Southeast and a lot of mid-sized markets with decent population growth adds up to a very valuable brand — as, of course, does the exceptional quality of the product on the field.

Still, the S.E.C.’s average of about 1.1 million fans per team — not counting Texas A&M — sets a slightly lower bar than the Big Ten’s. Clemson (1.8 million fans), Georgia Tech (1.7 million) or Virginia Tech would improve upon it, while Missouri and West Virginia (1.0 million) are aren’t far from the league average and would do more to expand the conference’s geographic footprint.

A.C.C.

The A.C.C. had about 900,000 fans per team prior to adding Syracuse and Pittsburgh, although with a wide range between the football-oriented schools on its southern frontier and some others that are better known for their basketball. Wake Forest, for instance, with only about 150,000 fans, has the smallest football fan base of any automatic-qualifying school.

New additions Syracuse and Pittsburgh actually come in slightly below the current league average, although not by much, and the league’s move to add them is understandable. Having added those two schools, there’s no reason the A.C.C. wouldn’t be interested in Connecticut and Rutgers, which have similarly-sized fan bases.

Big 12

Even with the losses of Texas A&M, Nebraska and Colorado, the Big 12 — as it stands on paper today — still has some football muscle, with about 8.1 million fans between the remaining 9 schools. Football is a big deal in this part of the country.

The conference’s survival would be in grave danger, of course, if Texas and Oklahoma were to leave as well. And there aren’t very many attractive expansion targets. Brigham Young, ranking 43rd in the country with about 700,000 fans, would be appealing enough from an economic standpoint. But schools like S.M.U., Houston and Rice have very small fan bases — under 200,000 each — in the extremely competitive market for Texas football.

One wonders if there isn’t some second-guessing about T.C.U. — scheduled to join the Big East next year — which also has to battle against other Texas teams but does a little better with about 400,000 fans.

If the Big 12 were to collapse, Iowa State, Kansas State and Baylor might have trouble latching on elsewhere: their fan bases each rank outside the top 50 nationally.

Pacific-12

The Pacific-12 plays plenty of good football, but the low avidity of college football fans in the Western United States means that it’s in the second-tier as a television product: only U.S.C. and U.C.L.A. have at least 1 million decided fans each. Despite their strong performance on the field, meanwhile, Washington and Oregon rank outside the top 40 in terms of their fan footprint. And other conference schools, like Oregon State, Stanford and Washington State, do poorly by major-conference standards.

As compared to these teams, new additions Colorado (0.5 million fans) and Utah (0.4 million) look tolerable — but their fan bases are likewise middling by national standards.

On the other hand, the Pacific-12’s latest targets — Texas, Oklahoma, Texas Tech and Oklahoma State — have about 5.1 million fans between them, which would expand the conference’s aggregate fan base by almost 70 percent. No wonder the Pacific-12 might be willing to make some academic and geographic compromises in order to get them.

Big East

Even before losing Pittsburgh and Syracuse, the eight Big East teams had only about 5.3 million fans between them — well below that of the other major conferences.

T.C.U., when it is added next year, won’t help matters much: it will bring only about 400,000 fans, ranking ahead of only Cincinnati and Louisville among current members.

Nor does the Big East have many good options as it tries to regroup. Assuming that other major-conference programs won’t be interested in it, the league could look toward the University of Central Florida, which has a decent base of about 500,000 fans, or even East Carolina (350,000 fans), but neither are premium brands.

Temple, essentially booted out of the conference in 2004 after failing to bring in enough revenue, might now seem like one of the least-worst options now. It only has about 200,000 football fans but at least brings the Philadelphia media market and good basketball. The Big East could also try to pressure Villanova, a member of the league for basketball, to upgrade its competitive football program to the F.B.S. level.

Even Marshall, Memphis or the University of Buffalo, also with about 200,000 fans each, could get a look if the conference were desperate to stay intact. So in theory could the service academies: Army has a radio affiliate in New York City and a proud football heritage.

Independents

Here’s one of those cliches that turns out to be valid: Notre Dame has a highly nationalized fan base. Its best markets — by the total number of fans, not market share — are New York, Chicago and Boston, each of which rank ahead of its native market of South Bend. It also has decent numbers of fans in markets as far afield as Los Angeles and Washington.

It’s no wonder, then, that the school has been reluctant to join a conference, which could limit its national exposure.

Brigham Young, as we mentioned, would be an attractive-enough addition for a conference like the Big 12. With about 700,000 fans, it ranks behind 42 automatic-qualifier schools — but ahead of 27 of them.

But it may instead be the case that the ranks of independent schools will expand rather than contract. West Virginia, for instance, was an independent for most of its history until 1990 and if it were an odd-team-out under realignment it could look toward that option again.

We’ll proceed very quickly through the remaining conferences.

Conference U.S.A.

In theory — but possibly not in practice — the most appealing targets here might not be those schools like Memphis or Houston that play second or third fiddle in a major market, but instead those like the University of Central Florida, East Carolina or Southern Mississippi that have built up decent fan bases in rural and exurban areas.

Mountain West

The pending additions of Hawaii, Fresno State and Nevada will bring in a combined 700,000 fans, making up for the loss of T.C.U. (400,000 fans). As compared to the other minor conferences, the Mountain West isn’t in terrible shape, although one assumes that recent addition Boise State — now the blue-chip member of the conference both competitively and economically — would jump at any opportunity to improve its lot in life. (Boise is a small market but has become very football-avid with the success of the Broncos.)

Sun Belt

Two things the Sun Belt Conference has going for it: it’s in the right part of the country for college football, and its teams are sufficiently obscure that they aren’t likely to be targets of raids from other conference — although Troy has decent numbers of fans.

Mid-American

A couple of these teams, like Temple and Buffalo, are in reasonably-sized markets, but they lack sufficient market share to be valuable economic entities.

Western Athletic

If the Big East or Big 12 think they have it rough, their position is enviable as compared to that of the Western Athletic Conference. Boise State is already gone, and the three remaining W.A.C. teams with the largest fan bases — Hawaii, Fresno State and Nevada — will be following them into the Mountain West Conference next year. The 5 surviving members of the conference have an average of only about 100,000 fans each.

***

Of course, the question that an analysis cannot address is whether through expansion a conference can become more than the sum of its parts — or if it instead risks becoming less.

The only two conferences that can feel completely secure right now are the Big Ten and the S.E.C..

They’re the two that have taken the most conservative attitude toward expansion over the past decade or two, waiting for programs of the caliber of Penn State, Nebraska and Texas A&M to become interested before increasing their ranks. They’ve been rewarded with extreme loyalty among their fan bases. In a sport where rooting interests are so highly localized, that goes a long way toward explaining their success.