There are 53 contestants; one from each state, plus representatives from the District of Columbia, Puerto Rico and the Virgin Islands.
They will be judged in several categories including swimsuit, evening gown, talent, and the all-important interview.
Miss Illinois is Megan Ervin of Quincy.
This is the 23-year-old's first time in Vegas.
"This is insane," she said. "The energy out here is just electrifying. So, safe to say I'll be back."
Go behind the scenes and meet all 53 women, every night this week in the special series "Miss America: Secrets Revealed" only on the Live Well Network. You can watch it at 7 p.m. on digital channel 7.2 over the air and on Comcast wide open west channels and RCN channels.
Then watch the next Miss America be crowned live on ABC7 this Saturday, beginning at 8 p.m.