The team will feature 269 women and 261 men competing in 25 of the 38 disciplines during the Games where the United States are expected to challenge China as the leading nation on the medals table.
"They are our nation's greatest athletes and embody what it means to be American," US Olympic Committee Chief Executive Scott Blackmun said.
"I'm also proud that for the first time in history, the US Olympic Team features more women than men."
More than half of the team will be competing at their first Olympics. Of the returning athletes, seven are attending their fifth Olympics and another 21, including Michael Phelps, will be appearing at their fourth.
Phelps already holds the record for the most gold medals at a single Olympics (eight) and a career (14) and needs to medal in three of his seven events in London to surpass Soviet gymnast Larisa Latynina's overall record of 18 total medals.
Natalie Coughlin needs just one more medal to join fellow swimmers Jenny Thompson and Dara Torres as the most decorated American female Olympian with 12 medals.
The oldest competitor is 54-year-old equestrian rider Karen O'Connor, while the youngest is 15-year-old swimmer Katie Ledecky.
"Whether competing at their first Games or fifth, the athletes on this team have made countless sacrifices, dedicating themselves to the pursuit of their Olympic dreams and to being their best both on and off the field of play," said Teresa Edwards, the team's chef de mission.