Next to the Obama posters, Save Senge placards and anti-moped bumper stickers, the names of candidates running for Cape and Islands state representative appeared in force last week, ahead of a highly contested Democratic primary on Sept. 16.

Candidates in the first open ticket race for the seat since Eric T. Turkington took the seat in 1989 soon after the district was established, are entering the final phase of their campaign, clamoring for the most effective way to reach potential voters and plotting a new electoral map as they go.

Dukes County — the Vineyard and the sparsely populated islands which make up the town of Gosnold — is the largest voting block in the district. However, with three candidates in the field, the Vineyard is also the most crowded. And it is more than 30 years since the Vineyard had its own representative in the state house.

From the Vineyard, three candidates are running: Daniel Larkosh of Vineyard Haven, Tim Lasker of Chilmark and Roger Wey of Oak Bluffs.

Falmouth resident David Moriarty is the sole candidate from the four Barnstable zones in the district. Tim Madden from Nantucket is running as a write-in candidate.

The winner of this primary will go up against two independent candidates for the election in November.

At a candidates forum in Falmouth Friday, Mr. Larkosh, Mr. Lasker and Mr. Moriarty were questioned on casinos, home insurance, the economy and the Cape Wind project among other issues.

Mr. Wey was unable to attend the event which was co-sponsored by the League of Women Voters and Falmouth Community Television and chaired by Mindy Todd, host of The Point on WCAI, Cape and Islands National Public Radio. Because of his write-in status, Mr. Madden was not invited to the forum.

Ms. Todd will interview the four ballot candidates in an hour-long special of The Point on Wednesday starting at 9 a.m.

Full interviews with the candidates will appear in the Friday Gazette.

As an electoral battleground, this state district is largely untested. In 1989 Mr. Turkington had no Vineyard opponents in the Democratic primary and in the following years no campaign has seriously threatened his seat. But after 20 years as state representative, he will not seek re-election this fall and the resulting contest has attracted more candidates than in any race during Mr. Turkington’s tenure combined.

Comprised of Nantucket and Dukes County and parts of Barnstable, the district contained 31,776 voters in 2006. Of these, Dukes County had 12,503 voters, the areas of Barnstable had 11,265 and Nantucket had 7,998. As one of 160 state representatives in Massachusetts, the successful candidate would vote on legal issues and lobby for state funding.

A supreme court ruling on one man, one vote in 1977 meant that Martha’s Vineyard was lumped together in a single district with Nantucket, Gosnold and parts of Falmouth. Previously the Vineyard had its own representative at the state house.

Mr. Larkosh, an attorney who grew up in Oak Bluffs and whose campaign signs were among those that dotted the Woods Hole Road this weekend, sees Falmouth as a key battleground.

“The Vineyard candidates have established bases,” he said, “Falmouth will be a swing state.”

A focus for Mr. Lasker, who is on his town planning board and affordable housing committee, will be on getting out the vote with phone calls, a trip to the Nantucket agricultural fair this weekend and handing out publicity material bearing the date Sept. 16.

“I’ve said this from the beginning but I think there’ll be a small turnout,” he said, adding that voters are not used to a highly contested state representative race, and have their eyes firmly trained on state and national elections in the fall.

Mr. Moriarty, who owns a construction company in Falmouth, said he will be standing outside the Vineyard Haven post office on Wednesday, ready to answer questions and is criss-crossing the Islands and Falmouth to get his message out.

Mr. Wey, who works full-time at the Oak Bluffs council on aging, is working weekends on his campaign.

“It’s very hectic, I’m spending a lot of time campaigning, going door-to-door,” he said. Mr. Wey has spent 20 years as an Oak Bluffs selectman and is a former county commissioner.

“I’m trying to find out the concerns of the people,” he added.

Mr. Madden who has been the Nantucket legislative liaison since 1989, is running on stickers, or as a write-in, after missing a February deadline to change his party affiliation from unenrolled to Democrat. Attempts to reach him yesterday on Nantucket were unsuccessful.

Mr. Turkington, who has not officially endorsed any candidate, nevertheless emphasized experience, pointing to Mr. Madden’s time as legislative liaison and Mr. Wey’s long tenure in several elected positions.

“Some experience in a publicly elected position is extremely valuable,” Mr. Turkington said.

He leaves office Jan. 6.