Andrew Cole Click from Tracy, California was taken to a local area hospital and pronounced dead at 11:45 p.m. on Sunday. There will be an autopsy to determine the cause of death.
The 23 people hospitalized were treated for various medical issues. Two women remained in the hospital and continue to receive treatment.
Eleven people were arrested, primarily for drug offenses, according to the San Bernardino County Sheriff's Department.
More than 80,000 people attended the event on Saturday, and more than 70,000 attended on Sunday.