Here's a look at the 22 Democrats who have thrown their hats into the ring and announced a campaign. We're going to keep updating this list through the campaign season as candidates announce their intentions or drop their bids.

Announced campaigns

Sen. Michael Bennet

AGE: 54

STATE: Colorado

KNOWN FOR: Bennet, the former superintendent of Denver Public Schools, was forced to hold off on entering the race following a diagnosis and subsequent treatment of prostate cancer in April. Having served in the Senate since 2009, Bennet has pitched himself in pre-campaign appearances and speeches as a pragmatic lawmaker who has a progressive voting record.

AGE: 76

STATE: Delaware

KNOWN FOR: Biden's long-anticipated announcement marks his third presidential campaign after he passed on a 2016 run. His name recognition, decades of experience and ties to former President Barack Obama are seen as his greatest assets. But his track record on -- and public response to -- making some women uncomfortable with his behavior could be an obstacle to gaining modern voters, some of whom may also think that the party needs new, more diverse representation.

JUST WATCHED Joe Biden announces 2020 presidential run Replay More Videos ... MUST WATCH Joe Biden announces 2020 presidential run 01:51

AGE: 49

STATE: New Jersey

KNOWN FOR: Booker, who boasts a Twitter following of more than 4 million people, gained national recognition during his tenure as Newark's mayor, at times answering pleas to shovel residents out after major snowstorms.

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AGE: 37

STATE: Indiana

KNOWN FOR: Known locally in South Bend, Indiana, as "Mayor Pete," Buttigieg served as a naval officer in Afghanistan. Buttigieg, though a long shot, would be the youngest and first married gay president if elected. He would also be the first candidate to go from the mayor's office to the presidency.

JUST WATCHED Young mayor joins crowded 2020 presidential race Replay More Videos ... MUST WATCH Young mayor joins crowded 2020 presidential race 02:13

AGE: 44

STATE: Texas

KNOWN FOR: The son of a Chicana activist, Castro served as mayor of San Antonio in 2009, focusing on education initiatives. Castro is currently the only Latino in the 2020 field, but whether he will be the only Texan will depend on former Texas Rep. Beto O'Rourke's decision about making his own bid.

JUST WATCHED Julian Castro announces presidential bid Replay More Videos ... MUST WATCH Julian Castro announces presidential bid 01:10

AGE: 55

STATE: Maryland

KNOWN FOR: A self-made businessman, Delaney at one point was the youngest CEO on the New York Stock Exchange. Delaney has been running the longest -- he declared his candidacy in July 2017 -- but is still working to gain name recognition.

JUST WATCHED President Trump has his first 2020 challenger Replay More Videos ... MUST WATCH President Trump has his first 2020 challenger 01:24

AGE: 37

STATE: Hawaii

KNOWN FOR: Gabbard is the first American Samoan and the first Hindu member of Congress, and brings her experience as an Iraq War veteran to the House Armed Services Committee. But she will have to overcome obstacles both old and new, including recent internal campaign turmoil and her controversial secret meeting with Syrian President Bashar al-Assad in 2017.

JUST WATCHED Tulsi Gabbard announces 2020 run Replay More Videos ... MUST WATCH Tulsi Gabbard announces 2020 run 00:29

AGE: 52

STATE: New York

JUST WATCHED Sen. Kirsten Gillibrand joins race for president Replay More Videos ... MUST WATCH Sen. Kirsten Gillibrand joins race for president 01:58

Former Sen. Mike Gravel

AGE: 88

STATE: Alaska

KNOWN FOR: Gravel isn't running for president to win -- he said so himself. According to his campaign announcement video , the former Alaska senator is running "not to win, but to qualify for the debates to push the field to the left on foreign policy and political reform." Gravel served in the Senate from 1969 to 1981, where he was known for his efforts to end the Vietnam War draft, and previously ran for president in 2008.

AGE: 54

STATE: California

JUST WATCHED A look at Sen. Kamala Harris' political career Replay More Videos ... MUST WATCH A look at Sen. Kamala Harris' political career 03:40

AGE: 67

STATE: Colorado

KNOWN FOR: As the head of Colorado from 2011 to 2019, Hickenlooper helped steer the state through several tragedies, including the 2012 shooting in a movie theater in Aurora that left 12 people dead and catastrophic wildfires and floods in 2013. Before his two terms as governor, he served as Denver's mayor for eight years, after opening a large brewpub there in 1988 that went on to help reinvigorate the LoDo area of Denver.

JUST WATCHED How Hickenlooper grew from brewery owner to governor Replay More Videos ... MUST WATCH How Hickenlooper grew from brewery owner to governor 02:05

AGE: 68

STATE: Washington

KNOWN FOR: Inslee, who has held elected office for much of the last three decades, has been an outspoken progressive executive since he became governor in 2013. He has been a vocal opponent of President Donald Trump, including suing the President after he tried to ban immigration from several Muslim-majority countries. Now, Inslee is running as the climate change candidate.

JUST WATCHED Washington Gov.: Not a moment for climate 'timidity' Replay More Videos ... MUST WATCH Washington Gov.: Not a moment for climate 'timidity' 13:55

KNOWN FOR: Klobuchar announced her run outdoors as it snowed, which she tied to her commitment to a "homegrown" campaign with "grit." The Minnesota moderate is looking to work across the aisle and win back fellow working class midwesterners.

JUST WATCHED Amy Klobuchar officially announces 2020 run Replay More Videos ... MUST WATCH Amy Klobuchar officially announces 2020 run 01:40

AGE: 44

STATE: Florida

KNOWN FOR: The child of Jamaican immigrants, Messam is a first-generation American who holds progressive views on immigration, guns and the environment. He was part of a group that sued the state of Florida in 2018 over a law that restricted his ability to create municipal gun regulations after he wanted a new amphitheater in his city to be a "gun-free venue."

JUST WATCHED Florida mayor announces 2020 presidential bid Replay More Videos ... MUST WATCH Florida mayor announces 2020 presidential bid 01:37

AGE: 40

STATE: Massachusetts

KNOWN FOR: Moulton, a Marine Corps veteran, raised his national profile after trying and failing to prevent Rep. Nancy Pelosi from reclaiming the speaker's gavel. He later voted for her after Democrats retook the House last year. Moulton's longshot bid is expected to focus heavily on veterans' issues and national security. If elected, he would be the youngest president in American history.

Seth Moulton

AGE: 46

STATE: Texas

KNOWN FOR: O'Rourke, a rising star in the Democratic Party, ran unsuccessfully for a Senate seat in 2018 while serving his third term in the House. With roots in El Paso, O'Rourke gained national attention during his Senate race when a video of him answering a question about NFL players kneeling during the National Anthem went viral. He made an off-the-cuff riff about the civil rights movement as he defended players for making their case "nonviolently, peacefully, while the eyes of this country are watching."

JUST WATCHED Beto O'Rourke's rise to the national stage Replay More Videos ... MUST WATCH Beto O'Rourke's rise to the national stage 02:01

AGE: 45

STATE: Ohio

KNOWN FOR: Ryan, whose district includes Youngstown, Ohio, enters the presidential race as a longshot candidate with less name recognition than most candidates and a far smaller political network. He has become most known in Democratic circles for his opposition to House Speaker Nancy Pelosi retaining her leadership positions, though he later voted for her when Democrats elected her speaker earlier this year.

AGE: 77

STATE: Vermont

KNOWN FOR: Sanders' democratic socialist platform gained significant traction during the 2016 primaries, when the independent senator who caucuses with Democrats ran against Hillary Clinton. His policy agenda includes various progressive proposals, many of which have been embraced by the Democratic Party, like expanding health care, broadening the social safety net and making higher education free.

JUST WATCHED Bernie Sanders announces 2020 presidential run Replay More Videos ... MUST WATCH Bernie Sanders announces 2020 presidential run 00:56

AGE: 38

STATE: California

KNOWN FOR: The Democrat who represents California's 15th Congressional District enters the race as a long-shot candidate in a crowded field. A frequent critic of the Trump administration, Swalwell has raised his profile by becoming a staple on cable television. He has focused on combating gun violence, and traveled to Iowa in December with Cameron Kasky, who's a survivor of the 2018 shooting at Marjory Stoneman Douglas High School in Parkland, Florida, and a co-founder of March for Our Lives.

AGE: 69

STATE: Massachusetts

KNOWN FOR: Warren was appointed as assistant to President Barack Obama and special adviser to the Treasury secretary in order to launch the Consumer Financial Protection Bureau. She was also appointed to a congressional oversight panel overseeing the $700 billion Trouble Assets Relief Program that was passed in response to the 2008 financial crisis.

JUST WATCHED Warren to face obstacles as she eyes 2020 bid Replay More Videos ... MUST WATCH Warren to face obstacles as she eyes 2020 bid 02:25

AGE: 66

STATE: Texas

KNOWN FOR: Williamson is best known for being a spiritual counselor to Oprah Winfrey and has written several best-selling books, including her debut "A Return to Love." She is calling for "a moral and spiritual awakening in the country" with her campaign.

JUST WATCHED Presidential candidate calls for moral awakening in US Replay More Videos ... MUST WATCH Presidential candidate calls for moral awakening in US 01:31

AGE: 44

STATE: New York

KNOWN FOR: Yang is an entrepreneur who launched Venture for America, a fellowship program that aims to connect recent grads with startups. He wants to give all Americans a universal basic income of $1,000 per month to address economic inequality.

Considering a run

Former Georgia House Minority Leader Stacey Abrams

Montana Gov. Steve Bullock

New York Mayor Bill de Blasio

Former Secretary of State John Kerry

Decided not to run

Sen. Sherrod Brown (took himself out of consideration on March 7, 2019)

AGE: 66

STATE: Ohio

KNOWN FOR: A liberal populist, Brown won three terms in Ohio, a state that has been trending Republican in recent years. Brown would've offered Democrats a candidate who could reconnect with voters in the Midwest. Before deciding not to run, he had embarked on a "listening tour" that included stops in the four key early voting states in the 2020 primary.

Former New York Mayor Michael Bloomberg (took himself out of consideration on March 5, 2019)

AGE: 77

STATE: New York

KNOWN FOR: Bloomberg hinted at a run for months before deciding against it. He had portrayed himself as a moderate against progressive projects such as Medicare-for-all but with extensive experience and campaign funds to put toward key Democratic issues such as climate change and gun control.

Former Attorney General Eric Holder (took himself out of consideration on March 4, 2019)

AGE: 68

STATE: New York

KNOWN FOR: Holder served as President Barack Obama's attorney general until 2015. Holder had told several Democrats -- and "The Late Show" host Stephen Colbert -- that he was "interested" in pursuing the nomination, but ultimately he opted not to launch a campaign.

Former Virginia Gov. Terry McAuliffe (took himself out of consideration on April 17, 2019)

AGE: 62

STATE: Virginia

KNOWN FOR: McAuliffe previously served as governor of Virginia and chairman of the Democratic National Committee and has an extensive fundraising network. He opted instead to help coordinate the campaigns of Virginia's local and national Democratic lawmakers "to make sure that we are blue" for 2020.

Sen. Jeff Merkley (took himself out of consideration on March 5, 2019)

AGE: 62

STATE: Oregon

KNOWN FOR: Merkley, the junior senator from Oregon, has focused on holding the Trump administration accountable on immigration policy, specifically family separations at the southern border. He opted in March to devote himself to his Senate re-election campaign over the next two years.

Dropped out

AGE: 48

STATE: West Virginia (dropped out January 25, 2019)