First of all, it is interesting to note to that 20 states are NOT represented in the tournament, so just making it in is an accomplishment.
From my count, below are the best-represented states in the 2011 NCAA men's basketball tournament. Since there a lot of ties with states sending 4 or 5 teams, I decided to average the seeding of each state's teams and rank them by that criteria. I was also motivated to do it this way because I'm a Hoosier...
---------------------------------------------
State (No. of teams) -> Avg. Seed
---------------------------------------------
Indiana (4) -> 6.75
Ohio (4) -> 7.00
California (4) -> 8.75
Pennsylvania (5) -> 9.60
Tennessee (4) -> 9.75
Virginia (5) -> 11.20
*Feel free to check my work*
As can be seen, Pennsylvania and Virginia are sending the most teams, but these teams are not of the highest average quality. Regardless, these six states represent a very large portion of the current College Basketball market.
North Carolina has 4 teams in the 2015 NCAA basketball tournament with an average seed of 5.75
North Carolina sent 5 teams to the 2012 NCAA Mens Basketball Tournament. NC State, UNC, Duke, Davidson, and UNC Asheville. I'm pretty sure this was the more than any other state. Virginia had a good showing as well. I'm not sure if Georgetown is in Virginia or Washington D.C.
4
The NCAA Men's Basketball Tournament went to 64 teams in 1985.
There were 53 teams in the 1984 NCAA Men's Basketball Championship (5 play-in games before the tournament).
1985
In 2000 there were 64 teams that played in the Division I basketball tournament.
Teams that are on the verge of being in or out of the NCAA tournament.
The 2012 NCAA men's basketball tournament included teams from 31 states and the District of Columbia.
The original NCAA Division 1 College Basketball Tournament 1939 field consisted of 8 teams.
64
UCLA with 11.
1939 was the first NCAA tournament. The teams participating were: Oregon, Texas, Oklahoma, Utah State, Villanova, Brown, Wake Forest, Ohio State Ohio State and Oregon played in the Final with Oregon winning the first NCAA Tournament.
There were no schools from New Jersey represented in the 2012 NCAA men's basketball tournament.