There are hundreds of Division I schools within the NCAA, but the amount varies between sports. The larger state and private schools generally field Division I teams in all sports.
There are considerably fewer Division I ice hockey teams than the other major sports, with teams concentrated in the Northeast, Midwest and Alaska. The only Power Five conference that sponsors ice hockey is the Big Ten, while all other conferences are ice hockey specific.
Football also has relatively few teams due to the high cost of the sport. Division I football teams hail from the Power Five conferences as well as smaller conferences, such as the American Athletic Conference, Conference USA, the Mid-American Conference, the Mountain West Conference and the Sunbelt Conference. Division I football has long been home to a few independent teams, which are Notre Dame, Brigham Young University and the United States Military Academy as of 2015.
It is much cheaper for universities to run varsity basketball teams, and it requires less space, so more schools sponsor Division I basketball teams than football or hockey. There are no independent teams in basketball, and there are Division I basketball conferences that do not exist in Division I football, such as the Patriot League, the Ohio Valley Conference, the Ivy League, the Big Sky Conference and the Big South Conference.