Elizabeth Warren officially joined Sunday a crowded field of Democrats vying to challenge President Donald Trump in 2020 -- already shaping up to be one of the largest and most diverse ever.
Warren joins a group of White House hopefuls that includes other high-flying female US senators, charismatic military veterans and a young gay mayor.
And it is likely to grow before the US primary season gets underway a year from now. Here are the first entrants in the presidential race, 21 months before the election.
Elizabeth Warren: At 69, the US Senate's consumer protection champion from Massachusetts became the first high-profile Democrat to enter the race when she announced a presidential exploratory committee on December 31.
She officially kicked off her White House run on Saturday. Warren is on the party's left flank, and built her reputation by holding Wall Street accountable for its missteps.
She is considered to have one of the best campaign organizations of any Democrat.
Trump has already taken aim at Warren, mocking her proclamation of Native American heritage.
Cory Booker: The 49-year-old US senator from New Jersey announced his candidacy February 1, evoking the civil rights movement as he promised to work to bring together a divided America.
Often compared to former president Barack Obama, Booker began his career as a community activist and rose to prominence as mayor of Newark, New Jersey. He was elected to the US Senate in 2013, the first African-American senator ever from that state.
A talented orator with a flair for the dramatic, he drew attention for his performance during confirmation hearings of Trump Supreme Court nominee Brett Kavanaugh.
Kirsten Gillibrand: This New York senator made a name fighting the battle to end sexual assault, especially in the military, before the #MeToo movement gained national prominence.
The 52-year-old, a fierce Trump critic, is making gender and women's issues a hallmark of her campaign.
Kamala Harris: The barrier-breaking senator from California who aspires to be the nation's first black female president announced her candidacy on a day honouring slain civil rights icon Martin Luther King, Jr.
The daughter of an Indian immigrant medical researcher mother and a Jamaican economist father, Harris, 54, began her career as a district attorney in San Francisco before serving as California's attorney general.
Julian Castro: A cabinet member in the Obama era and grandson of a Mexican immigrant, Castro announced his candidacy in English and Spanish on January 12 in the heat of the debate on immigration and border security.
At 44, the former mayor of San Antonio, Texas hopes to become the nation's first Hispanic president.
Tulsi Gabbard: At just 37, this congresswoman from Hawaii would be the first Hindu president if elected.
A supporter of liberal Bernie Sanders in the 2016 race, military veteran Gabbard was criticized for meeting with Syrian leader Bashar al-Assad during that country's civil war, and for anti-gay positions that she has since retracted and apologized for.
Pete Buttigieg: Nine months younger than Gabbard is the South Bend, Indiana, mayor who joined the race unveiling a resolutely future-looking and optimistic message to counter Trump's darker vision.
A US Navy veteran who put his mayoral duties on hold to serve in Afghanistan, Buttigieg would become the first openly gay nominee of any major party.
Andrew Yang: The 44-year-old tech entrepreneur launched his campaign with little fanfare in late 2017, warning against the dangers that automation presents to US workers.
He has advocated for a form of universal basic income as a way to reduce inequality.
John Delaney: An affluent Maryland businessman who served three terms in Congress, Delaney was the earliest Democrat to officially launch a bid, back in July 2017. He has crisscrossed the early-voting state of Iowa seeking to boost his name recognition.
Waiting in the wings: Several big Democratic guns have yet to commit, including former vice president Joe Biden and senators Bernie Sanders and Sherrod Brown. Senator Amy Klobuchar is expected to announce on February 10.
Former Texas congressman Beto O'Rourke is considering a run, as are billionaire New York ex-mayor Michael Bloomberg and Los Angeles Mayor Eric Garcetti.
Current and former governors are in the mix, too: Washington's Jay Inslee, John Hickenlooper of Colorado, Steve Bullock of Montana and Virginia's Terry McAuliffe.