“There are a lot of protests out there going to specific issues that are 10, 15 more votes here and there,” Mr. Stark said. “And by the time you move statewide, that’s a lot of votes. If it’s not resolved at the counties, it will end up at the state board, and the state board will have to sort it all out.”

As other Republican-controlled county elections boards rejected challenges from Mr. McCrory’s allies on Friday, the governor’s critics complained of baseless protests that they believed were intended to discredit North Carolina’s political climate.

“They’re silly, small in number, poorly researched and often defamatory,” Allison Riggs, a lawyer for the Southern Coalition for Social Justice, said of the Republican challenges. Ms. Riggs, who was monitoring proceedings in nearby Wake County, which includes Raleigh, the state capital, said some challenges brought by Mr. McCrory’s supporters had been easily rebuffed through a few minutes of internet research.

A spokesman for the McCrory campaign, Ricky Diaz, said Friday that the campaign expected people who brought the unsuccessful challenges to appeal to the State Board of Elections, which comprises three Republicans and two Democrats. County elections boards are made up of two Republicans and one Democrat.

The wrangling plays out in a state that has often been the epicenter of the national debate about voter identification requirements and other, Republican-backed changes to elections rules.

When North Carolina Democrats controlled the state government in recent decades, they sought to cement their franchise by enacting a string of laws that made it easier to register and vote, aiming in part to recruit more black voters. Combined with enforcement of the federal Voting Rights Act, the effect was profound: By 2012, turnout among African-Americans, who are overwhelmingly Democratic, soared to 68.5 percent, up from about 42 percent in 2000.

But when Republicans gained absolute control over the executive and legislative branches after the 2012 elections, they set about undoing the framework Democrats had built. After the United States Supreme Court struck down a crucial part of the Voting Rights Act, state legislators pared early voting, imposed a photo ID requirement and ended same-day registration. A federal appeals court ruled against much of that law in July, concluding it had targeted black voters with “almost surgical precision.” That decision faces an uncertain future before a Supreme Court poised to have a justice nominated by Mr. Trump.