In an unusual and historic state primary Tuesday, Martha’s Vineyard voters mirrored the state, strongly backing incumbent Democratic incumbent Sen. Edward Markey and Republican attorney Kevin O’Connor over their challengers, with a deluge of mail-in ballots and early voting raising voter turnout despite a slow day at the polls.

Statewide, Rep. Joseph Kennedy, 3rd conceded the race for the democratic senate nomination shortly after 10:00 p.m. on Tuesday night, with approximately 45 per cent of the vote to Mr. Markey’s 55 per cent. On the Republican side, the Associated Press declared Mr. O’Connor the victor over Shiva Ayyadurai by 10 p.m., after he grabbed 60 per cent of the vote to Mr. Ayyadurai’s 40 per cent.

The two candidates will face off against one another for the state’s junior United States Senate seat in November.

In Dukes County, Mr. Markey stormed to victory in all six Island towns and Gosnold, garnering over 60 per cent of the vote in every town and over 70 per cent in Chilmark and West Tisbury. He hovered between 61 and 63 per cent of the vote in the down-Island towns, and won 68 per cent of the vote in Aquinnah. In total, Mr. Markey earned 66 per cent of the Dukes County vote, outpacing his returns across other parts of the state.

The closely-watched race for the Democratic senate nomination had taken on national significance in recent weeks, as competing factions in the party have endorsed each candidate. Statewide, Mr. Kennedy fared well in many blue-collar precincts such as New Bedford, Fall River and Springfield, but was edged out solidly by Mr. Markey in other precincts, including in Greater Boston and in the Cape and Islands. Nantucket favored Mr. Markey by a similar margin as the Vineyard.

Mr. Markey’s victory marks the first time that a member of the Kennedy political family lost a statewide race in Massachusetts.

In the Island’s results for the Republican senate primary, Mr. O’Connor, an attorney mounting his first senatorial campaign, defeated Mr. Ayyadurai, a scientist, in Edgartown, Oak Bluffs, Chilmark and West Tisbury. Mr. Ayyadurai, who has previously run as an independent for senate, eked out victories in Tisbury and Aquinnah, with 45 votes to Mr. O’Connor’s 44.

Overall, Mr. O’Connor garnered over 60 per cent of the vote on the Island - nearly identical to his performance throughout the state.

In the Dukes County Commission race, all seven current commissioners were re-elected, with Christine Todd amassing the most votes and Keith Chatinover a close second. An eighth candidate, Hunter Moorman, had withdrawn his candidacy but remained on the ballot. Mr. Moorman received the fewest votes, thereby eliminating him from contention come November.

Turnout Islandwide was strong on a summery day that ushered in September, although many ballots were cast by mail or in early voting, according to town clerks who reported a slow trickle of voters throughout the day. Approximately 35 per cent of registered voters Islandwide cast votes in the respective primaries.

In the 2016 state primary election, which included a few close-fought local races, turnout was approximately 30 per cent.

But in 2020, town clerks in the down-Island towns reported that more than 40 per cent of voters either cast ballots early or voted by mail, a much higher proportion than in years past. The shift to mail ballots and early voting could signal a broader change come November, when Democratic nominee and former Vice President Joseph Biden Jr. is set to face off against Republican President Donald Trump.

Town-by-town turnout on Tuesday is as follows:

In Aquinnah, 192 of the town’s 400 voters cast ballots, for a 48 per cent turnout.

In Edgartown, 1167 of the town’s 3,925 voters cast ballots, for a 30 per cent turnout.

In Oak Bluffs, 1422 of the town’s 3,978 voters cast ballots, for a 36 per cent turnout.

In Tisbury, 1217 of the town’s 3,617 voters cast ballots, for a 34 per cent turnout.

In West Tisbury, of the town’s 2612 voters cast ballots, for a 43 per cent turnout.

The vote totals for the county commission are as follows: Leon Brathwaite, 2,879 votes; John Cahill 2,932; Keith Chatinover, 3,139; Tristan Israel, 2,693; Christine Todd, 3,208; Don Leopold, 2,414; Richard Wharton, 2,316 votes. Mr. Moorman received 2,087 votes.

All other races were uncontested.

On the Democratic side, incumbent Cong. Bill Keating received 164 votes in Aquinnah, 452 in Chilmark, 919 in Edgartown, 1117 in Oak Bluffs, 1064 in Tisbury and 935 in West Tisbury, for a total of 4,651 votes.

Incumbent state senator Julian Cyr received 153 votes in Aquinnah, 451 in Chilmark, 906 in Edgartown, 1081 in Oak Bluffs, 1045 in Tisbury and 927 in West Tisbury, for a total of 4,563 votes.

Incumbent state representative Dylan Fernandes received 156 votes in Aquinnah, 452 in Chilmark, 903 in Edgartown, 1073 in Oak Bluffs, 1064 in Tisbury and 926 in West Tisbury, for a total of 4,574 votes.

Incumbent first district councillor Joseph Ferreira received 133 votes in Aquinnah, 410 in Chilmark, 818 in Edgartown, 956 in Oak Bluffs, 922 in Tisbury and 784 in West Tisbury, for a total of 4,023 votes.

Incumbent register of the probate Daphne Devries received 138 votes in Aquinnah, 410 in Chilmark, 852 in Edgartown, 987 in Oak Bluffs, 966 in Tisbury and 819 n West Tisbury, for a total of 4,172 votes.

Incumbent Dukes County treasurer Ann Metcalf received 143 votes in Aquinnah, 409 in Chilmark, 920 in Edgartown, 982 in Oak Bluffs, 969 in Tisbury and 795 in West Tisbury, for a total of 4,218 votes.

On the Republican side, Helen Brady ran unopposed for the nomination to face Cong. Keating to represent the Cape and Island District in the House of Representatives. Ms. Brady receied five votes in Aquinnah, 21 votes in Chilmark, 93 votes in Edgartown, 98 votes in Oak Bluffs, 78 votes in Tisbury and 47 votes in West Tisbury, for a total of 342 votes.

Louisa Hufstader, Maia Coleman and Aaron Wilson contributed reporting.