The agency said those riders would receive various punishments, including suspensions and disqualifications.
The scope of evidence against the team is "overwhelming," according to the agency.
"The USPS Team doping conspiracy was professionally designed to groom and pressure athletes to use dangerous drugs, to evade detection, to ensure its secrecy and ultimately gain an unfair competitive advantage through superior doping practices," the agency said.
Armstrong became a household name not only in Europe, where cycling is wildly popular, but also in the United States, where the sport traditionally attracted little attention before he embarked on a remarkable stretch between 1999 and 2005 and won seven consecutive Tour de France titles. Persistent accusations that he used performance-enhancing drugs grew as he won more Tours.
Author and cycling journalist Bill Strickland compared the case to baseball's "Black Sox" scandal, when eight Chicago White Sox players conspired with gamblers to throw the 1919 World Series. But he said Armstrong is "not interested in ever admitting to his guilt, and he just wants to move on right now."
"Despite this evidence and despite all the evidence that has come out, he's got a strong core of people who believe in him and will always believe in him because of his link to fighting cancer," said Strickland, who chronicled Armstrong's 2009 return to the Tour de France in a 2011 book.
But how Armstrong might move on is unclear.
"Certainly, he's not going to be able to move on within the sport," Strickland told CNN. "It seems likely that all of his Tour victories will be stripped. He won't be allowed to participate in any sports that are signatories of WADA, the World Anti-Doping Agency. But he's found a few triathlons to do in the meantime."
And he said the allegations could lead to the reopening of a criminal case against Armstrong that federal prosecutors closed without charges in February.
"What's next is years and years of fighting if the criminal case is reopened," Strickland said.
The USADA opened its own case, which does not carry criminal penalties, in June.