Series producers say nearly 50,000 people have turned out in the first four cities where tryouts have been held. Auditions for the singing contest's 10th season started July 15.
The crowds of 16,000 in Nashville and 17,000 in East Rutherford, N.J., are among the biggest the show has seen - eclipsed only by the 22,000 that auditioned in Washington, D.C., for season four, a show spokeswoman said.
Earlier this year, "American Idol" expanded the pool by lowering the age eligibility a year, from 16 to 15 years old. The maximum age to audition remains 28.
The final auditions are set for Austin, Texas, on Aug. 11 and San Francisco on Aug. 19.