This year's marches have been under recent criticism over comments made by Women's March co-founder and co-chair Tamika Mallory.
In Washington, demonstrators arriving by vehicle, bus or subway converged on the city's Freedom Plaza as they prepared to march defiantly past the nearby Trump International Hotel on Pennsylvania Avenue.
Occupy New Hampshire Seacoast and other groups also are hosted a women's march in Portsmouth.
Several hundred "sister marches" are scheduled to take place nationwide on the same day, although some of the events are being organized by groups such as the Women's March Alliance that have rebuked the Women's March and anti-Semitism.
Demonstrators hold up their banners as they march on Pennsylvania Avenue during the Women's March in Washington on Saturday.
Those wanting to march for women in New Hampshire had their pick of locations.
Last year, many women were galvanized by the confirmation of conservative judge Brett Kavanaugh to the US Supreme Court, despite allegations that he committed sexual assault as a teen.
Rep. Ayanna Pressley addresses the Boston Women's March.
Teresa Shook, the first woman to float the idea of a women's march, has called for the movement's four co-presidents - Mallory, Carmen Perez, Linda Sarsour and Bob Bland - to resign.
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Sadly, despite a celebrated beginning, it has become clear that the organizing done under the guise of the Women's March is a political movement created to advance leftist causes and elect Democrats to higher office.
Democratic New York Congresswoman Alexandria Ocasio-Cortez, who was part of the women's wave elected to Congress in November, attended both rallies.
Inaugural marches drew millions to march in cities across the U.S.
"I am just so fearful for their future if continue on this road", she told Al Jazeera, pointing to the government shutdown, US President Donald Trump's immigration policies and what she called the "abdication of Congress of their duties".
But turnout was muted compared to years past as organizers in Boston, New York, Chicago and Los Angeles bemoaned the organizational challenges caused by the refusal of Women's March leaders to condemn all forms of antisemitism, and to recognize Israel's right to exist as a Jewish state.
In an interview with PBS due to be broadcast Sunday, Mallory refused to answer a question on Israel's right to exist.
The third annual Women's March is underway in dozens of cities across the country on Saturday, including Waterfront Park in San Diego.