Cora Medeiros, the former Tisbury selectman and businesswoman who was long considered the unofficial town matriarch, died on Sunday, Mother’s Day, at home in Vineyard Haven surrounded by her family. She was 85 and had been out of the public eye for some time due to illness.

She served for 14 years as a selectman, not contiguously, from the 1970s to the 1990s, ran her gift shop the Sea Chest in the old SBS building across the street from the Steamship Authority terminal on Water street, and for decades organized and presided over the Tisbury Street Fair — the event that celebrates the town birthday every year on July 8. Mrs. Medeiros was one of four founders of the fair, all of them women, and she loved it even more than her own birthday, which fell on the Fourth of July.

“That was her thing, the street fair, it was her baby,” said Aase Jones, the longtime town administrative assistant who retired this year. “She was catalyst for a lot of things. I have a soft spot in my heart for her. I know she loved this town and she had a heart of gold.”

Born in New Bedford, Cora Simpkin was educated in the Fairhaven public schools and attended the St. Lubec School of Nursing. In 1949 she was working as a waitress at the Mansion House in Vineyard Haven when her engagement to Raul Medeiros was announced in the Gazette. They were married the following year in a candlelit evening ceremony at Christ Methodist Church in Vineyard Haven. She and Raul had six children. He died in 2000 at age 72.

Cora became active in civic affairs at a time when few women held elected office on the Vineyard. — Mark Lovewell

Cora became active in civic affairs and town politics in an era when few women held elected office on the Vineyard. She was elected selectman three times, beginning in 1975, when she served a single term. In 1981 she was elected again for a single term. Then in 1986 she was elected and served until 1994.

She was fond of filing petitions with the state legislature and kept her own counsel, even though at times it made her unpopular.

In the 1980s she campaigned for the town to pull out of the Martha’s Vineyard Commission and then took an opposite position later on, urging the town to return to the regional planning agency — which it did in 1984.

Decades later, when powerful politicians in New Bedford wanted to expand the Steamship Authority board of governors, Cora joined the march to Beacon Hill, advocating for the two Islands to keep control of their boat line. “We don’t want this bill. New Bedford shouldn’t have a vote until they are a port,” she told the Gazette at the time.

In the 1990s she led the effort to build a town senior center; a plaque of appreciation in her name now hangs on the wall of the center.

And of course Cora was synonymous with the street fair, which she started in 1976 with Shirley Frisch, Joan Montamat and Darlene Pachico. Today the fair endures as a giant Main street block party with food and booths of every description.

“She put the street fair on the map,” said longtime Tisbury selectman Tristan Israel this week. He added: “She was certainly in her time as a woman groundbreaking in her involvement in politics. No one had the town’s interest more in mind than Cora Medeiros. Not that I agreed with her on everything — but she was the town of Tisbury.”

Others had similar memories, echoing the widespread view that at heart Cora was a mother — to her children, grandchildren and her town.

“She was unwavering and passionate in her advocacy of what was best for Tisbury,” said Ray LaPorte, a longtime Island investment advisor who served briefly as a selectman. He continued: “Although one might not have agreed with her on some issues or her style, you had to admire her effectiveness and many accomplishments. She was my business landlady and called me Sunshine. She appointed me to my first town position on the zoning board of appeals. Ironically and unintentionally years later, I defeated her at the polls, filling the unexpired term of my friend Ed Coogan as selectman. She never ran for office after that, but still called me Sunshine.”

In an email, Rachel Orr, a former reporter for the Gazette who covered Tisbury, recalled Mrs. Medeiros’s tenacity on certain issues, especially the years-long effort for the town to take ownership of the Manter well.

“Selectmen’s meetings were never boring when Cora was on the board,” Ms. Orr wrote. “She had a strong will, a strong personality — she used both to get the Manter well on line. That was a pretty complicated thing: not only did it require building significant water infrastructure, but it required closing the septage lagoons because they were in the zone of contribution and purchasing additional land to guarantee protection of the well site. Cora worked hard to put together the partnerships that made it happen — for example, the land bank bought Tisbury Meadow to help the town with aquifer protection — and stood up year after year pushing the town meeting to pass the required warrant articles.”

Ms. Orr, now a year-round resident of Vineyard Haven and mother who is active in town affairs, also noted: “She rarely referred to the town as Vineyard Haven in meetings. For Cora, the town was always Tisbury . . . . pronounced Tizbry. She was very loyal and proud of her town.”

Visiting hours for family and friends will be held on Friday from 6 to 8 p.m. in the Chapman, Cole and Gleason Funeral Home in Oak Bluffs. A funeral service will be held on Saturday, May 14, at 10:30 a.m. in St. Augustine’s Church in Vineyard Haven. Interment will follow in the Oak Grove Cemetery in Vineyard Haven.

Cora’s favorite color was yellow and she loved flowers, her daughter Joan said this week. Flowers will be appreciated.

Donations in her memory can be made to the Tisbury Senior Center, P.O. Box 207, or to the American Legion Post 257, PO Box 257, both in Vineyard Haven, MA 02568.