Martha’s Vineyard voters will head to the polls today to cast ballots in the state primary election, which features a lengthy line-up of contested races.

Polls will be open in every Island town from 7 a.m. to 8 p.m. Voting locations are the Aquinnah town offices, Chilmark Community Center, Edgartown town hall, the Oak Bluffs library, the emergency services building in Vineyard Haven and the West Tisbury public safety building.

The Gazette will post election results online as they become available.

The ballot includes contested races for state senator, state representative, Dukes County sheriff, and Register of Deeds. The primary ballot is party affiliated; most of the contested primary races are on the Democratic ballot.

According to the Secretary of State, there are 14,644 voters registered for the primary in Dukes County.

The Gazette emailed customized questionnaires to candidates for most offices asking them to answer two general questions: why Martha’s Vineyard voters should elect them and what their qualifications were for office. The legislative candidates were also asked about their priorities, while the county office candidates were asked why the job they are seeking should matter to local voters.

Click on the candidates' names below to read their responses. Independent candidates are included even though they will not appear on the ballot until the Nov. 8 general election.

State Senate

Four candidates are in the primary runoff for the state senate seat being vacated by Sen. Dan Wolf — Democrats Julian Cyr and Sheila Lyons and Republicans James H. Crocker Jr. and Anthony Schiavi. (A third Republican, Brian Mannal, will appear on the ballot but has withdrawn from the race.)

State Representative

Seven candidates are vying for the state representative seat now held by retiring Rep. Timothy Madden, although only five  — all Democrats — will appear on the primary ballot: Dylan Fernandes, Michael G. Heylin, T. Ewell Hopkins Jr.,  Jessica Lambert and Timothy W. Soverino. Two other people — Jacob Ferry and Tobias Glidden are running as independents.

County Sheriff

Two Democrats, Robert W. Ogden and Marc R. Rivers, are in a primary runoff for county sheriff to replace retiring sheriff Michael McCormack. Neal J. Maciel, an unenrolled candidate from Vineyard Haven, will be on the ballot in November.

Register of Deeds

Five candidates are running for Register of Deeds, though only four of them — all Democrats — will appear on the primary ballot. The Democratic candidates are Paulo DeOliveira, Laura Johnson Hairston, Candace A. Nichols, and Eve L. Vincent. Martina Thornton is running as an independent. The winner in November will replace retiring Register of Deeds Dianne Powers.

U.S. Congress

Incumbent U.S. Rep. Bill Keating is unopposed in the Democratic primary for the seat in Congress that represents Martha’s Vineyard, but two Republicans — Mark Alliegro and Tom O’Malley — are facing off in the primary for the right to oppose him in November. Two unenrolled candidates, Chris Cataldo and Anna Grace Raduc, will appear on the general election ballot, as will Paul J. Harrington, a member of the United Independent Party.

Mr. Alliegro, of East Falmouth, is a scientist and educator who ran unsuccessfully in the 2014 Republican primary. A former senior scientist at the Marine Biological Laboratory in Woods Hole, he is currently a professor of molecular biology, cell biology and biochemistry at Brown University.

Mr. O’Malley, of Marshfield, is a retired Navy commander who later held management positions with PanAm Shuttle and American Airlines.

Representative Keating, of Bourne, a career public servant who previously served as district attorney for Norfolk County, is seeking his fourth term.

County Commission

Five candidates for county commission appear on the Democratic primary ballot: John S. Alley, Leon Arthur Brathwaite 2nd, David Jeffrey Holway, Christine Catherine Todd and Gretchen Tucker Underwood. One candidate, Norman L. Perry, appears on the Republican ballot. But with seven seats open there are no contested races. Two unenrolled candidates, Tristan Israel and Robert Zeltzer, will also appear on the general election ballot for county commission.

Note: this story has been updated to correct Timothy W. Soverino's party affiliation. He is a Democrat.