The team, which was announced on Saturday by the U.S. Olympic Committee (USOC), will contest 244 of 306 medal events.
The Americans topped the gold medal (46) and overall medal (104) tables at London 2012.
The record number of women on the U.S. team tops the previous mark of 289 by China in 2008.
It is the second time the American roster has featured more females than males.
“I am especially excited for the historic achievement of our women’s delegation which is a true testament to the strength and growing number of women’s sport opportunities in the United States,’’ Scott Blackmun, the USOC Chief Executive Officer (CEO) said.
The American team includes 191 returning Olympians, such as equestrian rider Phillip Dutton and shooters Emil Milev and Kim Rhode who are each heading to their sixth Games.
Among those going to their fifth Olympics are swimmer Michael Phelps, middle-distance runner Bernard Lagat, tennis player Serena Williams and beach volleyballer Kerri Walsh-Jennings.
Phelps, who owns an Olympic record 18 gold medals, will swim in at least three events in Brazil.
Runner Allyson Felix, the most decorated U.S. Olympic woman with four gold medals and six overall, makes a fourth Games appearance, competing in the 400 meters and probably the 4×400 relay.
Among the strongest medal favourites are the women’s basketball team and gymnast Simone Biles in the women’s all-around.
The women’s rowing eight seek to continue a dynasty on the world stage, as they have not lost an Olympic or world championship title since 2006.
Dutton, 52, will be the oldest team member, with 16-year-old table tennis player Kanak Jha the youngest.