Many of the protesters said they feared some of the progress made could be reversed under Trump.
Tens of thousands of people have marched in the US capital for LGBT rights, in one of the biggest protests since President Trump took office.
Many of the those attending said they felt their community was under threat from the new government.
The organisers said dozens of cities across the US would also hold rallies.
The march comes on the eve of the first anniversary of the shooting in a gay Florida nightclub, Pulse, which killed 49 people.
It began in the downtown area of Washington, DC, and then passed in front of the White House and continued on to the National Mall.
People from as far as California, Colorado and Kentucky held aloft placards bearing slogans such as “Make America Kind Again”, “Remember Pulse” and “We Are Human”.
“We are here to stand and be counted. There’s a growing hostile rhetoric from the White House and we don’t like the point of direction, ” said Daniel Dunlop from Atlanta, who was there with his partner Leonard and Leonard’s parents.
“The fact that Trump did not even recognise Pride month is an omen of what’s to come, and we need to mobilise now.”
Ernie Emirich, from Washington, said hard-fought rights were under threat. ” [President Trump] has claimed to be a friend of the community but his actions have shown him to be hostile to many of the issues that are important to us.”
Not everyone mentioned the new president when asked why they were marching.
“I’m a lesbian and I want to support the rights of gay and transgender people, ” said Ione Martin.
“Hate and intolerance still exist. We have marriage equality but that doesn’t change people’s attitudes.”
The White House was asked for comment on the issues raised by the march but did not respond to the request.
During the campaign, Mr Trump made repeated overtures to the LGBT community, including a pledge in his nomination acceptance speech last year. As one protester put it on Sunday, he “draped himself in the rainbow flag”.
But four months into his presidency, many in that community feel he has done little to back that up.
They point to his rescinding of guidance to schools on dealing with transgender pupils, and his silence on this month’s Pride celebrations, an event usually marked by the White House. And they fear some of his conservative cabinet members want to derail some of the legislative progress made in recent years.
Some protesters also said Trump policies on immigrants and Muslims had stoked their anger, and there was a wider goal of equality to strive for.
A small number of people said it was not just about President Trump, but it is clear the new occupant of the White House has mobilised the LGBT community in a way not seen in years.
