The squad was made up of 23 men and 24 women, and led, once again, by the mercurial Michael Phelps, who qualified for his fourth Olympics.
Phelps qualified for five individual events which, with the addition of the three relays, would have seen him compete in the same events he won on Beijing four years ago.
But he dropped the 200 metres freestyle from his programme to save his energy for the relays, where the Americans face a huge challenge defending the 4x100m freestyle.
"The relays are always serious," head coach of the men's team Gregg Troy said.
"That's a tough program Michael swims. It's really tough. He's a little bit older, and those older guys don't recover quite as quickly."
Colorado teenager Missy Franklin also qualified for seven events, including the relays. She is the first American female swimmer to do so and has already emerged as the new star of the women's team heading to her first Olympics.
"I think she's proven that she can handle the highest pressure with her performance here over the last week," women's head coach Teri McKeever said.
"She's 17-years-old, but she handled this meet like a seasoned professional."
Ryan Lochte qualified in five events and could add another in the relays. His rivalry with Phelps promises to be one of the highlights of the Olympics.
"We embrace that. It's good for the sport and it's good for the athletes," Troy added.
"But by the same token, those same fans, they need to understand there's some other guys in the world who are really good. I don't believe that Michael or Ryan have carte blanche that it's just the two of them."
The oldest member of the team was 36-year-old Jason Lezak, who qualified as a reserve in the 4x100m freestyle relay. The youngest was 15-year old Katie Ledecky, the winner of the 800m freestyle.
There was not a single world record set during the eight-day championship in the American Midwest but Troy said he was expecting all the swimmers would go faster in London.
"I'm concerned about everything. It's a pretty big world. There is a lot of good swimmers out there," he said.
"If we take anything lightly we're making mistakes. At the same time, we know where we are at. Our athletes are in a good spot.
"We have 21 great days planned for them. I think we're going to respond really well. It's competition, and we like to compete."
The selected swimmers will assemble in Tennessee next week for a training camp before heading to France to finish off their preparations before the Games start on July 27.
"I'm excited about how the women's team has unfolded," McKeever added.
"You know that the rest of the world is looking at how fast we're swimming and I think there are great possibilities to continue to get better."
US Olympic swimming team
Michael Phelps (200m individual medley, 400m individual medley, 100m butterfly, 200m butterfly)
Ryan Lochte (200m freestyle, 4x200m freestyle, 200m individual medley, 400m individual medley, 200m backstroke)
Ricky Berens (200m freestyle, 4x100m freestyle, 4x200m freestyle)
Conor Dwyer (400m freestyle, 4x200m freestyle)
Matt McLean (4x200m freestyle)
Charlie Houchin (4x200m freestyle)
Peter Vanderkaay (400m freestyle)
Matt Grevers (100m backstroke, 4x100m freestyle)
Nick Thomas (100m backstroke)
Brendan Hansen (100m breaststroke)
Eric Shanteau (100m breaststroke)
Tyler Clary (200m butterfly, 200m backstroke)
Clark Burckle (200m breaststroke)
Scott Weltz (200m breaststroke)
Nathan Adrian (100m freestyle, 4x100m freestyle)
Cullen Jones (50m freestyle, 100m freestyle, 4x100m freestyle)
Jimmy Feigen (4x100m freestyle)
Jason Lezak (4x100m freestyle)
Anthony Ervin (50m freestyle)
Tyler McGill (100m backstroke)
Davis Tarwater (4x200m freestyle)
Andrew Gemmell (1500m freestyle)
Connor Jaeger (1500m freestyle)
Alison Schmitt (200m freestyle, 400m freestyle, 4x100m freestyle, 4x200m freestyle)
Chloe Sutton (400m freestyle)
Rachel Bootsma (100m backstroke)
Missy Franklin (100m backstroke, 200m backstroke, 100m freestyle, 200m freestyle, 4x100m freestyle, 4x200m freestyle)
Breeja Larson (100m breaststroke)
Rebecca Soni (100m breaststroke, 200m breaststroke)
Dana Vollmer (100m butterfly, 4x200m freestyle)
Claire Donahue (100m butterfly)
Elizabeth Beisel (400m individual medley, 200m backstroke)
Caitlin Leverenz (200m individual medley, 400m individual medley)
Lauren Perdue (4x200m freestyle)
Shannon Vreeland (4x200m freestyle)
Alyssa Anderson (4x200m freestyle)
Ariana Kukors (200m individual medley)
Camille Adams (200m butterfly)
Kathleen Hersey (200m butterfly)
Micah Lawrence (200m breaststroke)
Jessica Hardy (50m freestyle, 100m freestyle, 4x100m freestyle)
Lia Neal (4x100m freestyle)
Amanda Weir (4x100m freestyle)
Natalie Coughlin (4x100m freestyle)
Katie Ledecky (800m freestyle)
Kate Ziegler (800m freestyle)
Kara Lynn Joyce (50m freestyle)