10 That I know of in Division I. I can't imagine the smaller Division II or III schools have the money for domes or retractable roofs.
3 FBS: Syracuse, Idaho, Tulane (superdome),
Northern Michigan University in Marquette, MI has a dome. It was built for Olympic purposes, but the football team has a field made of turf inside.
The Kibbie Dome in Moscow Idaho is one of two that i know of. It is currently undergoing renovations to make it more modern since it was build in 1975 (at that time named the engineering feat of the year). Its home of to the Idaho Vandals Football, Basketball and Track and Field teams as well as graduation concerts and the Lionel Hampton International Jazz Festival.
11 Teams in the IFL
But there are nine Arena Leagues.
And each vary I'm sure.
Tulane, Idaho and Syracuse
There are approximately 119 College Football teams.
All states have college football teams, but not even half of the states have NFL teams.
I know there are some teams from Maryland in the Diamond Football League, and there is an indoor football league as well.