What to Know
Election officials said counting the provisional ballots in Burlington and Ocean counties could take well into next week.
The race is the only one remaining without a projected winner in the 31 total districts in Pennsylvania, New Jersey and Delaware.
MacArthur has been closely associated with President Trump while Kim is a former Obama adviser.
The tightly contested congressional race in New Jersey remains undecided as Democratic challenger Andy Kim claimed victory while incumbent Republican Rep. Tom MacArthur stated more votes need to be counted.
"I am proud to announce that we have won this hard-fought race," Kim said to his supporters during a speech Wednesday night.
Shortly after Kim's comments, MacArthur released a statement of his own.
"This has been a hard fought campaign and like Andy Kim, I'm ready to see it come to an end," MacArthur wrote. "I have always said that I will be guided by the voters of the district and there are nearly 7,000 more of them who haven’t been heard from yet. We must ensure that their votes - and all votes - are counted in a transparent way that protects the integrity of this election."
MacArthur is seeking his fourth term in the Garden State's Third Congressional District. The race between MacArthur and Kim remained too close to call Wednesday, and election officials say it could come down to provisional ballots.
Those officials said counting the provisionals could take well into next week.
The district stretches from the Delaware River to the Jersey Shore in Ocean County.
MacArthur led Kim by 2,315 votes out of a total 270,501 cast on Tuesday. But after some 26,000 mail-in ballots were added up Wednesday, Kim held a more than 2,500-vote lead late Wednesday afternoon.
After the updated totals, Kim won Burlington County 101,903 to 69,090, while MacArthur beat Kim in Ocean County, 76,868 to 46,677, on Election Day.
In addition to the thousands of mail-in ballots in Burlington County, thousands more remained to be counted in Ocean County, where MacArthur's strongest support is.
Election officials in both counties said tallying the mail-in votes would likely be done by the end of Wednesday, but the provisional ballots would take days.
"That’ll be a process that will continue over the next more than likely week," Ocean County elections chairwoman Marie Peterson said.
The race is the only one remaining without a projected winner in the 31 total between Pennsylvania, New Jersey and Delaware. Pennsylvania has 18 congressional seats, New Jersey has 12 and Delaware has one.
In Pennsylvania, women candidates created a wave that joined a larger national trend. In New Jersey, a second woman was elected to join incumbent Democratic U.S. Rep. Bonnie Watson Coleman. And in Delaware, the incumbent Lisa Blunt Rochester won a second term.
That means a total of seven women from the tri-state region would be part of the 31-member congressional coalition.