Sen. Kamala Harris is finalizing plans to announce her entry into the 2020 presidential race around Martin Luther King Day, multiple outlets reported late Wednesday night citing sources close to the California Democrat.

Harris would be the fourth person so far to join the race for the Democratic nomination, though that number is expected to balloon to dozens of candidates by the time campaign season kicks into full swing.

Harris and her aides are still working out the final details of her announcement rally, including the date, which could be Martin Luther King Day, Jan. 21, CBS News reported.

Advisers to Harris do not want to link the senator too closely to San Francisco, but they still prefer the Bay Area to be the backdrop for her rally, per CBS’ reporting.

“San Francisco is viewed as a very nutty place by people outside of California, and frankly, by a lot of people inside California,” Democratic strategist Darry Sragow, who teaches political science at the University of Southern California, told CBS News.

Harris was born in Oakland and began her public career as a two-term district attorney there.

Though California is Harris’ home state, her team wants to locate its headquarters on the East Coast, near the major cable news outlets and within quicker flying distance to some of the early Midwestern and East Coast primaries and caucuses, such as Iowa, New Hampshire and South Carolina.

One source told Roll Call that Baltimore, with its three nearby airports and close proximity to Washington, stands atop the shortlist.

The city is a 40-minute train ride and roughly an hourlong drive from Washington, allowing Harris more flexibility to make it back to the Capitol on short notice for votes in the Senate.

A Baltimore headquarters would also allow staffers who join the campaign to commute from their homes and apartments in Washington instead of having to find new housing in another part of the country.

Harris has been on tour recently promoting her new memoir, “The Truths We Hold: An American Journey,” a milestone for many recent major party nominees for president.

At a book event Wednesday night at George Washington University in D.C., Harris batted away reporters’ questions about a pending 2020 announcement.

In the first CNN/Des Moines Register/Mediacom poll of the cycle of likely Iowa caucus-goers last month, Harris had support from 5 percent of those surveyed, placing her fifth among the field of 20.

She will have to play catchup with Sen. Elizabeth Warren of Massachusetts and former Vice President Joseph R. Biden, Sen. Bernie Sanders of Vermont, and former Texas Rep. Beto O’Rourke if the latter three decide to run. Warren announced earlier this month that she is in the race.

An early December CNN poll showed 4 percent of Democrats nationally supported Harris among a list of 22 other potential candidates. The 54-year-old senator has polled in the low single digits in other early polls.

Watch: Now That That’s Over (Mostly) Roll Call Looks Ahead to 2020