They first began in response to the presidency of Donald Trump. Now held for the first time since Joe Biden was elected, the annual Women's March spawned nationwide protests and drew thousands to American capital on Saturday.
At the centre of this year's march is abortion, with demonstrators demanding continued access in a year when conservative lawmakers and judges have put it in jeopardy.
The demonstrations took place two days before the start of a new term for the Supreme Court that will decide the future of abortion rights in the United States, after appointments of justices by President Donald Trump strengthened conservative control of the high court.
In the past year America's most restrictive laws were passed in Texas, which has banned most abortions since early last month.
That case now being heard in a federal court where a judge will have the option to overturn the ban. On Friday he was urged by President Joe Biden to do precisely that.
In Washington protesters rallied in a square near the White House, waving signs and chanting. Some wore T-shirts reading simply “1973," a reference to the landmark Roe v. Wade decision, which made abortion legal for generations of American women.
"I believe that it's crucial for women today to really fight for what we fought for when Roe v. Wade was the case that decided women have the rights to make their own choices. I don't believe that it's right for anybody to tell women that they don't have a right to choose what they do to their own bodies," said Madison Berkowitz, a communications student.
"We should be able to have our own choice on what we do with our own bodies, period. And I'm sick and tired of somebody else trying to own me or tell me what I can or cannot do. So, we've got to put a stop to it," added Laura Bushwitz, a retired teacher from Florida.
Organisers say the Washington march was among hundreds of abortion-themed protests held around the country.
On the West Coast, thousands marched through downtown Los Angeles to a rally in front of City Hall. Protesters chanted “Abortion on demand and without apology: only revolution can make women free!”
In New York, Governor Kathy Hochul spoke at rallies in Seneca Falls and then Albany. “I'm sick and tired of having to fight over abortion rights," she said. "It's settled law in the nation and you are not taking that right away from us, not now not ever.”
In Springfield, Illinois, several hundred people rallied on the Old State Capitol square. Prominent among them were the Illinois Handmaids, wearing red robes and white bonnets reminiscent of the subjugated women of Margaret Atwood’s novel “The Handmaid's Tale” and carrying signs that said, “Mind Your Own Uterus” and “Mother By Choice.”
At an unrelated event in Maine, Republican Senator Susan Collins called the Texas law “extreme, inhumane and unconstitutional” and said she was working to make Roe v. Wade the “law of the land”, working with two Democrats and another Republican.
But an opponent of women's access to abortion called this year's march theme “macabre.”
“What about equal rights for unborn women?” tweeted Jeanne Mancini, president of an anti-abortion group called March for Life.
The Women's March has become a regular event — although interrupted by the coronavirus pandemic — since millions of women turned out in the United States and around the world the day after the January 2017 inauguration of Donald Trump.
Trump endorsed punishing women for getting abortions and made appointment of conservative judges a mission of his presidency.