Former D.C. Council aide Christina Henderson claimed victory Wednesday in the crowded race for an at-large council seat, as partial returns showed her with a solid lead and her closest competitors conceded.

Henderson, a 34-year-old first-time candidate, is on track to join the council after a heated campaign against nearly two dozen contenders, including three men who had appeared on the ballot before. Incumbent Robert C. White Jr. (D-At Large) also handily won a second term.

With Democrat Joe Biden easily capturing the District’s three electoral college votes on Tuesday, according to Edison Research, the at-large D.C. Council race emerged as the highest-stakes contest on the ballot, with the potential to reshape the balance of power in the liberal city.

Only one candidate — in this case White — could run as the Democratic nominee, which meant he was generally favored to win in the deep blue city. That left the other candidates competing for the seat vacated by retiring council member David Grosso (I-At Large).

White was running far ahead of the field Wednesday, capturing about a quarter of the vote. Henderson, a former top staffer to Grosso who ran as an independent with his endorsement had about 15 percent of the vote.

Former lawmaker Vincent B. Orange Sr. was behind her, and slightly ahead of candidates Marcus Goodwin and Ed Lazere — who both have run before. They all called Henderson to concede, and Mayor Muriel E. Bowser (D) and Council Chairman Phil Mendelson (D) both offered her congratulations.

“The people of the District of Columbia have spoken: your Zip code should not determine your access to the best that D.C. has to offer,” Henderson wrote in an email to supporters. “I am honored that voters have endorsed this vision for the District and chosen me to make it a reality as your next At-Large Councilmember.”

The council appears likely to have a female majority next year, with Democrats Brooke Pinto in Ward 2 and Janeese Lewis George in Ward 4 also far ahead in their quests for full four-year terms for seats previously held by men.

Longtime D.C. Del. Eleanor Holmes Norton (D) was easily reelected to another term, and D.C. voters appeared to have approved a ballot measure to decriminalize psychedelic plants by a wide margin.

The results came after a smooth Election Day, which followed a massive shift to mail and early voting as residents and officials sought to avoid the long lines that marred the June primaries.

It worked: Elections officials reported minimal waits and crowding on Tuesday. At some polling places, campaign volunteers outnumbered the voters they were trying to woo.

At least 280,000 D.C. voters already cast ballots through Monday, or about 90 percent of overall turnout in the 2016 presidential election. Overall voter turnout figures were not immediately available Tuesday evening.

The at-large council race morphed into a referendum on the city’s increasingly liberal direction after two of the most fiscally conservative lawmakers lost in the Democratic primary and Grosso declined to seek a third term, unleashing a free-for-all to succeed him.

Public campaign financing and easier ballot-access requirements enabled a host of other candidates to run as independents.

They included Markus Batchelor, vice president of the D.C. State Board of Education; Mónica Palacio, former director of the D.C. Office of Human Rights; shadow representative Franklin Garcia; and neighborhood commissioners Chander Jayaraman and Alexander Padro. Claudia Barragán, Mario Cristaldo, Calvin Gurley, Kathy Henderson (who is unrelated to Christina Henderson), A’Shia Howard, Jeanné Lewis, Eric Rogers, Michangelo Scruggs, Keith Silver and Will Merrifield also ran. Republican Marya Pickering, Statehood Green Party nominee Ann Wilcox and Libertarian Joseph Bishop-Henchman were on the ballot. Rick Murphree was on the ballot but dropped out of the race.

The at-large race probably will have a significant impact on the future of city hall politics with the business-friendly centrist wing and the left-leaning flank of the council vying for a majority on the 13-member body.

Henderson cast herself as a “pragmatic progressive” candidate who would straddle the middle, touting her expertise on the inner workings of government and her lived experience as a Black woman and mother of a toddler.

“She seemed more of a centrist rather than the far left,” said Charles Stodghill, who lives in Ward 4 and voted early for Henderson and White last week. He noted that Henderson hasn’t gone as far as others in declaring the city has too many police officers.

Lazere, who ran to the left of Henderson, said liberal voters should still see her strong showing as a win.

“Her winning, particularly given that people who didn’t win next in line were far less progressive than her, I do think is a sign D.C. residents are looking for candidates of progressive values,” Lazere said in an interview Wednesday morning.

Lloyd Thompson, 58, voted for Orange, a self-described fiscal conservative, because he was worried the council was drifting too far left.

“A lot of the new people on the council, sometimes they seem to go a little off-kilter,” said Thompson, an accountant who cast his ballot at Turkey Thicket Recreation Center. “Orange can bring them back. They’re a little too progressive for me.”

Others, like Matthew Brown of Glover Park, cheered on the increasingly liberal city leadership.

Racial tension and navigating gentrification are the main points candidates are facing for the D.C. Council at-large election. (The Washington Post)

“Any chance I get I’m trying to get more progressive voices at all levels of government,” said Brown, 36, who voted early last week for Lazere and Batchelor, two of the furthest-left candidates in the race. “D.C. is a wonderfully blue district, but there’s still income inequality, and police aren’t treating people on the eastern side of the city in a fair way.”

But it was President Trump, not local officials, who was on the minds of many D.C. voters casting their ballots.

“I can’t really feel that I know that Biden is going to win; I can’t really feel that I know Trump is gonna win,” said Emma Ward, 76, decked out in a sash from her time in 2011 as Ms. Senior District of Columbia. She had stopped by King Greenleaf Recreation Center to check out the atmosphere, even though she dropped off a ballot two weeks ago.

“I just don’t feel great about not knowing what could possibly happen,” she said.

The other council contests were low-profile affairs.

Council member Brooke Pinto (D-Ward 2), who won a June special election to fill the vacancy triggered by longtime lawmaker Jack Evans’s resignation, appeared on track to handily win a full four-year term following spirited opposition from independents Randy Downs and Martín Miguel Fernandez and Statehood Green Party candidate Peter Bolton.

Council members Vincent C. Gray (D-Ward 7) and Trayon White Sr. (D-Ward 8) appeared to have sailed to reelection, while Janeese Lewis George, who defeated incumbent Brandon T. Todd (D-Ward 4) in the primary, appeared to have won the general election over nominal opposition.

D.C. elections officials had been looking to avoid the debacles that derailed the primaries, when some voters had to wait in line past midnight and others never received the mail-in ballot they requested.

For the general election, officials mailed each voter a ballot, established 55 drop-off sites throughout the city and operated 32 early-voting locations. The D.C. Board of Elections kept 95 voter centers open on Election Day, including several “supercenters” at large facilities including Nationals Park and Capital One Arena, but short of the usual 144 traditional polling places.

In interviews at polling places, many early voters said they wanted the solace of seeing their ballot count without relying on mail delivery and without enduring Election Day waits.

“I want to make sure my vote is counted,” said Nakisha Howard, a 37-year-old Southeast Washington resident who came out on the first day of early voting last Tuesday at Hillcrest Recreation Center. “And I want to see and physically do it myself. I don’t want anyone else but me to handle my ballot.”