A voting booth at St. Dunstan’s Episcopal Church in McLean, Va. (Jahi Chikwendiu/The Washington Post)

The number of voters in Virginia who have cast early ballots ahead of the November elections is dramatically up compared with last year, suggesting an electorate that is energized by several hotly contested races for Congress that are spread across the state.

Virginia allows voters to cast “absentee” ballots in person if they have valid excuses for not being able to vote on Election Day.

Nearly 78,000 people have completed ballots since absentee voting began Sept. 15 — more than double the number who voted early by this point last year, according to an analysis of voting data by the nonprofit Virginia Public Access Project.

That number is still shy of the 123,221 absentee ballots cast during the 2014 midterm elections, state data shows.

But with a little less than three weeks before the Nov. 6 elections, local election officials say this year’s absentee totals are on pace to eclipse 2014 and may even approach the turnout for the presidential election of 2016, when a near-record 496,452 Virginians cast their ballots early.

“It’s actually quite shocking,” said Richard Keech, deputy director of the elections office in Loudoun County, which has seen a 239 percent jump in absentee voting this year, with 11,106 ballots either already cast or mailed to voters so far.

“This would be the first time without a president on the ballot that we’ve seen this kind of increase,” Keech said.

Fairfax County, the state’s largest jurisdiction, has seen a roughly 100 percent increase since last year, with 21,582 absentee votes cast so far, officials said. Nearby, Prince William County, the ­second-largest jurisdiction, has climbed by about 114 percent to 4,693 absentee ballots cast.

Republicans and Democrats alike are angry over a range of issues, including immigration, health care and the controversy surrounding Supreme Court Justice Brett M. Kavanaugh’s confirmation after he was accused of sexual assault.

And President Trump adds another dimension to the election. In Virginia, broad discontent with the Trump administration last year fueled a wave of Democratic victories in state legislative races and the gubernatorial contest that helped level the balance of power in Richmond, said Quentin Kidd, director of the Wason Center for Public Policy at Christopher Newport University in Newport News.

“Turnout is going to be up everywhere where there is a competitive race going on,” Kidd said, predicting that Democratic enthusiasm will continue in Virginia. “What we don’t know is how big that wave is going to be.”

The VPAP analysis shows that early voting has skyrocketed in several hotly contested House districts.

In the 2nd Congressional District, where Rep. Scott W. Taylor (R) leads retired Navy Cmdr. Elaine Luria (D) in a recent poll, absentee voter turnout increased by 90 percent, with 4,911 absentee ballots cast. Roughly half of those votes hailed from Virginia Beach City, which has swung back and forth between the two parties in recent elections.

In the 5th Congressional District, where distillery owner Denver Riggleman (R) and journalist Leslie Cockburn (D) are locked in an increasingly bitter race to fill the seat being vacated by Rep. Thomas Garrett (R), absentee ballots were up by 117 percent to 6,090. There, the number of ballots cast in heavily Democratic Charlottesville were up by 213 percent to 673.

And, in the 7th Congressional District, where Rep. Dave Brat (R) is fighting a challenge by former CIA officer Abigail Spanberger (D), absentee ballots climbed by 133 percent to 6,248. The 182 absentee ballots cast in historically Republican Spotsylvania County jumped 171 percent from last year.

Sen. Tim Kaine (D), who is leading Republican challenger Corey Stewart by 20 points in some polls, has been spending time and money trying to boost Democrats running for the House.

Democratic and Republican state party leaders said they have been stepping up efforts to get more people to the polls early, and each side saw signs of hope in the response this year.

Stephen J. Farnsworth, a political science professor at the University of Mary Washington in Fredericksburg, said absentee voters are typically motivated.

“The surge in interest allows candidates to focus more on voters who are less inclined to make it out on Election Day,” he said.

“The more people vote early, the more campaigns can concentrate on people about whom they have doubts are going to show on Election Day,” he said.

In Fairfax on Thursday, a steady trickle of voters walked into the county government center to cast ballots.

“This will be a big turnout year,” said Kate Hanley, secretary of the county’s board of elections. “Not yet presidential, but we could get there.”

Several voters in the predominantly Democratic county said their dislike of Trump motivated them to vote early, a sentiment that could signal trouble for Rep. Barbara Comstock (R) in that portion of her 10th Congressional District as she tries to fend off her challenger, state Sen. Jennifer Wexton (D-Loudoun).

Catherine Wydeman, who lives in Rep. Gerald E. Connolly’s 11th Congressional District and voted for the Democrat, said she was motivated by a host of Democratic causes, including immigration reform and the Black Lives Matter movement.

“Everything is kind of scary,” Wydeman, 34, said.