Correction: Earlier versions of this article, including in the Jan. 3 print edition of The Washington Post, misstated the point during the petition-circulation period at which incumbent Mayor Vincent Gray launched his reelection campaign.

The crowded race for District mayor was culled slightly Thursday as all but four of 13 candidates seeking the Democratic nomination submitted enough voter signatures to tentatively qualify for the April 1 primary ballot.

That sets up the District’s widest and most competitive primary field since at least 1998, when then-Chief Financial Officer Anthony A. Williams beat three sitting D.C. Council members for the Democratic nomination.

This year’s Democratic field includes the incumbent, Vincent C. Gray, who did not join the race until nearly halfway through the eight-week petition circulation period. He is joined by four sitting council members — Muriel Bowser (Ward 4), Jack Evans (Ward 2), Vincent B. Orange (At Large) and Tommy Wells (Ward 6) — as well as a former State Department official, Reta Jo Lewis, and a prominent restaurateur, Andy Shallal.

The campaigns of those seven candidates each reported collecting at least twice the 2,000 signatures needed, with Evans’s campaign saying it collected more than 10,000 voter signatures.

The D.C. Board of Elections released the names of candidates who had qualified for the primary, but not the number of signatures. The petitions will made available for public review Saturday, a board spokeswoman said.

The candidates

See the Democrats who have picked up nominating petitions for the District's April 1 primary and find candidate profiles and video coverage of the race.

There is no direct advantage to gathering more signatures than the minimum, except as insurance against challenges to the signatures’ validity.

But the exercise is, for most candidates, only partly about securing access to the ballot. It is also an opportunity to gather contact information from potential voters and to flex a campaign’s organizational muscle.

In a race that, at this point, has seen little polling, the number of signatures collected becomes — along with fundraising, endorsements and sign-hanging — an imperfect but significant measure of a campaign’s strength.

Gray’s late entry appeared to have caused little trouble for his petition-circulation efforts, with his campaign manager claiming to have submitted more than 8,000 signatures .

Democrats Carlos Allen, a musician and promoter, and Christian Carter, a government contractor, also turned in petitions before the evening deadline. Four little-known candidates who picked up nominating petitions — Michael Green, Luis I. Poblete, Frank Sewell and Octavia Wells — did not turn them in.

After the petitions are made available for review, the campaigns and registered voters have until Jan. 13 to file challenges. The Board of Elections has until Feb. 6 to resolve those challenges and finalize the ballot.

No Republican candidate filed petitions, marking the second consecutive mayoral primary without a GOP candidate on the ballot. Faith, a single-named Adams Morgan resident who has sought the mayoralty on numerous occasions dating back to the 1970s, was the sole Statehood Green candidate to submit petitions.

Bruce Majors is likely to become the first D.C. mayoral candidate to appear on the Libertarian Party ballot; the city’s Libertarians are holding their first-ever primary this year.

To qualify for the ballot, Majors had to gather signatures from two of the party’s roughly 170 registered voters.