Chris Markey will remain as the 9th Bristol District’s representative to Beacon Hill.

The Dartmouth Democrat defeated 21-year-old challenger Cameron Costa for the nomination in this year’s Massachusetts Primary on Tuesday, his first contested race since 2014.

According to unofficial results from Dartmouth and New Bedford, Markey received 3,585 total votes, while Costa got 1,266. Of those votes, 3,124 Dartmouth residents voted for Markey, while 928 cast their ballots for Costa.

No Republican ran in the state representative primary, leaving Markey to cruise to a seventh term come the general election in November.

“I’m pretty happy with the results,” Markey said. “It was great to have support from so many community leaders.”

Costa said that while he’s disappointed with the results, he is proud of running what he called a “clean campaign.”

“As we know, they can get nasty sometimes,” he said. “I set out to challenge an incumbent on a base of different beliefs of what many people told me they felt they needed here — I don’t regret it.”

Costa said he plans to finish up his graduate degree at UMass Dartmouth.

Though defeated, he said he will remain politically active in 2022, noting that he plans to push for the passage of the Fair Share Amendment, which would create a 4% tax on a portion of a person’s income above $1 million.

According to advocates of the amendment, which will appear on the ballot on Nov. 8, tax money would be put toward public and higher education, along with transportation.

He added that Markey offered to sit down and talk about how to incorporate aspects of his progressive platform to “benefit the people of this district.”

“I look forward to taking him up on that and continuing the relationship,” Costa said.

Markey said he is also looking forward to chatting with Costa about the issues he said affect the North End of New Bedford, which was added to the legislative district in 2021.

“He’s a constituent now,” Markey said. “I want to make sure that I listen to what he, and the people who supported him, are concerned with.”

One such issue, Markey said, is addressing traffic problems on Braley Road.

“This is a neighborhood where people schedule appointments around when school is getting in and out because of the traffic,” he said.

Another issue Markey said he hopes to tackle is helping farmers deal with overpopulation of deer and coyotes who are “ruining crops” across the state.

“We need to get rid of some archaic laws for that,” he said.

The removal and cleanup of toxic soil in Dartmouth’s Bliss Corner neighborhood is also a top priority, he said.

In other races, Dartmouth voters overwhelmingly re-elected incumbent District Attorney Thomas Quinn III over challenger Shannon McMahon, a former prosecutor.

Quinn received 3,093 votes, while McMahon got 920. No Republican candidate was on the ballot for this election.

According to preliminary results, Quinn won the countywide vote 64.2% to 35.8%.

Similar to Costa, McMahon said she had nothing but pride in her campaign.

“Regardless of the outcome tonight, we put Tom Quinn on notice that he can no longer skate by,” she said in a statement. “We let him know that we are paying attention. And we let him know that his best is just simply not good enough.”

Incumbent State Sen. Mark Montigny (D-New Bedford) ran uncontested in his primary election and will face no challenger for the general election.

In the three-way Democratic race for Bristol County Sheriff, Attleboro Mayor Paul Heroux emerged victorious over former prosecutor Nick Bernier and former Somerset Police Chief Geroge McNeil.

According to the unofficial results, Heroux received 2,158 votes. Bernier came in second with 1,064, while McNeil received 618.

The Associated Press called the race for Heroux at 9:30 a.m. Wednesday. The Attleboro mayor will next face off against incumbent Sheriff Thomas Hodgson, who faced no opposition on the Republican ballot, in the fall election.

“I’d like to thank the voters and my team for tonight’s victory,” Heroux said in a statement. “I look forward to the next two months of making my case to the voters of Bristol County that not only is it time for change in the Bristol county jail system, but that my vision is a forward thinking, modern approach to corrections.”

Statewide, Massachusetts Attorney General Maura Healey was declared the winner of the Democratic primary election for governor by the Associated Press Tuesday evening.

She will face off against former Whitman State Rep. Geoff Diehl, who defeated Wrentham businessman Chris Doughty for the Republican nomination. Diehl was declared the winner of the Republican primary by 10:15 p.m. on Tuesday.

In Dartmouth, Diehl received 877 votes, while Doughty got 614.

Republican Lt. Governor candidate Leah Allen beat out Kate Campanale in Dartmouth precincts, and Democratic candidate Kim Driscoll captured a win locally against her two opponents, Tami Gouveia and Eric Lesser.

The statewide election day will be on Nov. 8. Early voting for the state election will be between Oct. 22 and Nov. 4.

This story will be updated as more information comes in.