Joining the Big Ten champion Illini as No. 1s on Sunday were North Carolina and Duke from the Atlantic Coast Conference and the Huskies of the Pac-10.
Illinois (32-1) was assigned to the Chicago regional. North Carolina (27-4) will be at Syracuse, Duke (25-5) will be in Austin and Washington (27-5) in Albuquerque.
The Huskies, the surprise of the No. 1s considering they were ranked 14th in the latest Associated Press poll, took advantage of Kentucky's loss Sunday in the Southeastern Conference championship game to move onto the top line. Tournament officials said the Wildcats would've been a No. 1 seed had they won that game.
It's the sixth time in eight years two teams from the same conference were seeded No. 1. The last time was 2003, when Oklahoma and Texas of the Big 12 were No. 1 seeds.
The Illini won't get any frequent flyer miles in this tournament as they will play the first and second rounds in Indianapolis with the regional in Chicago and the Final Four is April 2 and 4 in St. Louis.
Illinois, which opens play Thursday against Northeast Conference champion Fairleigh Dickinson, was followed in the Chicago regional by second-seeded Oklahoma State, which won the Big 12 tournament; No. 3 Arizona, the regular season Pac-10 champion, and fourth-seeded Boston College, co-champions of the Big East.
Two teams went into last year's tournament with just one loss. Saint Joseph's lost in the regional finals to Oklahoma State, while Stanford lost to Alabama in the second round.
Washington opens play Thursday in Boise against Montana, the Big Sky champions.
The No. 2 seed in the Albuquerque regional was Wake Forest, which was considered a sure No. 1 seed candidate; but the Demon Deacons lost in the ACC tournament quarterfinals to North Carolina State. Gonzaga, the West Coast Conference regular season and tournament champion, was seeded third and Louisville, which swept the Conference USA titles, was No. 4.
North Carolina, which lost to Georgia Tech in the ACC tournament semifinals, has defending national champion Connecticut as its No. 2 seed with Kansas at No. 3. Florida, which beat Kentucky in the Southeastern Conference title game, is at No. 4.
The Tar Heels will face the winner of Tuesday's play-in game in Charlotte on Friday. Oakland (12-18), which won the Mid-Continent Conference tournament, will play Alabama A&M, the Southwestern Athletic Conference champion, on Tuesday night in Dayton. Oakland is the only team in the field with a losing record.
Duke, which won the ACC tournament Sunday for the sixth time in seven years, has Kentucky as its No. 2 seed with Oklahoma the third seed and Syracuse, the Big East tournament champions, the fourth seed. Duke will open Friday in Charlotte against Delaware State.
The Big East and Big 12 each has six teams in the field, one short of the record seven, while the Big Ten, the SEC and the ACC each has five. The other multiple bids leagues were Conference USA and the Pac-10 with four each, the Missouri Valley with three and the Big West, Mountain West, West Coast and Western Athletic Conference with two each.
The last of the at-large teams were all No. 11 seeds: Alabama-Birmingham (21-10), Northern Iowa (21-10) and UCLA (18-10).
Among the bubble teams that were not invited were: DePaul (19-10), Maryland (16-12), Saint Joseph's (19-11) and Notre Dame (17-11).
The pod system, which tried to keep schools as close to home as possible for the first and second rounds, will have North Carolina and Duke both in Charlotte, while Illinois and Kentucky both head to Indianapolis. Oklahoma State was sent to Oklahoma City, while Connecticut and Syracuse are in Worcester, Mass.
Arizona extended the longest consecutive NCAA streak with its 21st straight appearance while Kansas has the second-longest run at 16 straight years.
Niagara, the 14th seed in the Austin regional, had the longest run between appearances. The Purple Eagles were last in the tournament in 1970 when Calvin Murphy was their star.
Delaware State, Oakland, Southeastern Louisiana and Alabama A&M are all making their first NCAA tournament appearances.