Washington DC - Delaware state senator Sarah McBride won a seat in the House of Representatives on Tuesday, making her the first openly transgender politician elected to Congress.

The Democrat was the comfortable winner against Republican John Whalen III, US news networks projected, as she built up an unassailable lead with around two-thirds of ballots counted.

"Delaware has sent the message loud and clear that we must be a country that protects reproductive freedom... and that this is a democracy that is big enough for all of us," she said in a statement posted to social media.

McBride told CBS in a recent interview her other priorities would be "affordable child care, paid family and medical leave, housing, health care."

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Transgender rights have become a hot-button issue in the US election – with the participation of trans people in competitive sports and the issue of access to gender-affirming care for minors triggering fiery debate.

The LGBTQ+ Victory Fund congratulated McBride for "making history" in American politics.

"Sarah's voice is vital, and she will continue to be a tireless advocate for her constituents and community," the group said.

The fund has identified at least 62 transgender candidates running this year across the country – nearly double the 34 who ran in 2020.

They include former Spanish teacher Mel Manuel, who identifies as transgender and nonbinary and was running for a seat in Louisiana, one of the most traditionally conservative in the country.

But they were trailing Republican heavyweight Steve Scalise by almost 50 percentage points in the early stages of the count.

For more on Tuesday's Election Day results, check out TAG24's live coverage of this year's biggest races.