In New York, floats and marchers paraded down Fifth Avenue, many clad in outrageous colourful outfits.
The theme of this year’s procession is “The Fight for Love and Life”, and coincides with the 25th anniversary of the emergence of the deadly AIDS epidemic that decimated America’s gay communities.
“AIDS isn’t over until it’s over for everyone,” read one banner.
New York Mayor Michael Bloomberg, meanwhile, in his weekly radio address urged city residents to undergo HIV testing.
“AIDS has taken the lives of nearly 90,000 New Yorkers. We should never forget that for too long, fear, ignorance, and neglect allowed AIDS to flourish, contributing to its deadly toll in our communities,” the New York mayor said.
Despite the sombre anniversary, marchers revelled in the freedom to express their sexuality.
“Everyone else has a chance to express their affection freely, and for one day in New York, you can be free and not feel embarrassed,” said Roberto Hermosilla of Miami, attending his ninth parade.
Drag queen and singer Kevin Aviance rode atop a fake elephant on a circus-themed float, with the parade marking his triumphant return after he was viciously beaten. Police have charged four young men over the attack.
Similar celebrations marked the day across the United States.
In San Francisco, the capital of gay America, thousands lined Market Street for the 36th annual parade to see marching bands, dancers and floats, many bearing corporate logos of major companies.
“There’s much greater acceptance in corporate America,” said Michael Crowe, 63, who said high-profile corporate sponsorship is new to the event.
America’s gay communities have been rocked by several setbacks in recent weeks.
The US Episcopal Church backtracked on Wednesday by asking its local diocese to “exercise restraint” in the controversial ordination of gay clergy, in an attempt to avoid a split in the global Anglican church.
Gay rights activists were outraged last week after a controversial Pentagon document reaffirmed a finding that classified homosexuality as a “mental disorder,” along with mental retardation and personality disorders.
And while the US Senate earlier this month narrowly rejected a measure calling for a constitutional amendment banning gay marriage — a measure strongly backed by conservative US President George W Bush — Christian conservatives bent on outlawing same-sex marriage have prevailed in numerous individual US states in recent months.
Massachusetts is the only state to allow gay marriage after its Supreme Court legalised it in May 2004.
However six US states are expected to pass prohibitions on gay marriage.
The gay marriage issue in particular seemed to be on the minds of many protesters who streamed along the length of 5th Avenue, New York’s Main Street, with some participants wearing tee shirts declaring “Marry Me: It’s about time.”
“It’s a hot topic, because it’s like the last hurdle before we can achieve equal rights,” said Phil Mannino, co-chair of New York’s “Heritage of Pride” group which organized the gay pride march.
One of the largest parades was held in Atlanta. Georgia’s Supreme Court on Tuesday will hear arguments on whether to reinstate a constitutional ban on gay marriage.