Dorothy King, of the Long Island Collection

Dorothy T. King, who was in charge of the East Hampton Library’s Long Island Collection for 31 years, died at Southampton Hospital on Saturday following a stroke. She was 84.

A resident of Gerard Drive in Springs for 43 years, Ms. King retired from the library in 2002 but continued to volunteer there until 2005. She was “a gold mine of information,” Ann Chapman, a library board member, told The Star for a story about Ms. King after her retirement.

“There aren’t very many people not only with a store of firsthand personal knowledge — she is a King, after all — but also the professional ability to get that information out,” Helen A. Harrison, curator of the Pollock-Krasner House and Study Center, told the reporter. Ms. King’s forebears were among East Hampton’s Town’s first settlers.

The Long Island Collection, started by Morton Pennypacker in 1930, contains one-of-a-kind documents including letters, deeds, town trustee records, whaling logs, and more. Ms. King helped to collect, catalog, organize, and protect thousands of documents at a time when grants and other funds were not available for such tasks. In 1997, she helped oversee the expansion of the Long Island Collection.

After the collection began to be digitized in 1999, Ms. King helped people from all over the world find information on their genealogical roots or for historical investigations. She not only assisted in research on material within the library’s walls, but helped to connect researchers with people living in the community.

Over the years, she helped filmmakers looking for historical background for movies such as “Amistad” and “Grey Gardens,” and countless authors. She used to keep track of all the acknowledgements she received in books, but eventually abandoned the idea when there were too many. “Origins of the Past: The Story of Montauk and Gardiner’s Island” (2013), the fifth volume of a series relating to the history of East Hampton Town, was dedicated to Ms. King.

Tom Twomey, the library board’s chairman, said that “Ms. King has had a profound influence on generations of amateur East Hampton historians. I remember the rainy Saturday that I wandered into the Long Island Collection and met her for the first time. As with so many others, Dorothy got me hooked on local history.”

She knew “not only where each item was located, but its provenance and related documents as well,” Mr. Twomey said. “History was in her blood. She devoted her life’s work to making the Collection accessible to all the professional and amateur historians in the community.”

Ms. King was born on Sept. 27, 1929, at her grandparents’ house on Fireplace Road in Springs. Her parents were Clarence E. King and the former Elizabeth Baker. In 1936, her father drowned at sea while trying to save a friend who had fallen overboard. Her mother later married Charles A. Raynor.

Having always had an interest in East Hampton’s history, Ms. King began working for the library while a high school student, earning 25 cents an hour. After graduating from East Hampton High School in 1947, she went on to earn a degree in library science from the State University at Geneseo, and worked as a school librarian in Valley Stream. From 1948 to 1952 her home was on Gardiner’s Island, where her mother and stepfather were caretakers.

She received a master’s degree as a library media specialist from Long Island University in 1971, the same year she took over the management of what was then known as the Pennypacker Collection. In a 1998 interview with The Star, Ms. King credited Hazel Griffin, who was Mr. Pennypacker’s assistant, with indexing the collection and becoming her mentor.

She kept busy in retirement, volunteering for the food pantry at the Springs Presbyterian Church and Meals on Wheels and as a member of the Springs Historical Society and the Accabonac Protection Society. She remained a member of St. Luke’s Episcopal Church in East Hampton, where her mother had belonged.

She enjoyed gardening, knitting, walking on Gerard Drive, and attending the yoga program at the East Hampton Town Senior Citizens Center twice a week. And, of course, she loved to read. “She was an avid reader, sometimes a book a day up until last week even. The library had a hard time keeping her in books,” said her niece Deanna Tikkanen of Springs.

There was also the business of moving bricks for small patios on her property. Brick by brick, she would rearrange them, even recently.

“She was a very kind and gentle lady,” Ms. Tikkanen said. Her aunt never married and had no children, and her nieces and nephews were like children to her, she said.

In addition to Ms. Tikkanen, she is survived by another niece, Carol MacPherson Elms of East Hampton, and five nephews, four of whom, John C. MacPherson, Clarence E. King III, David M. King, and Sidney Fields, live in the East Hampton area. Barry MacPherson lives in Virginia. Ms. King was predeceased by both her siblings, Clarence E. King Jr. and Alice Bell MacPherson Field.

Visiting hours were at the Yardley and Pino Funeral Home in East Hampton on Monday, with funeral services the next day at the Springs Presbyterian Church, the Rev. Anthony Larson officiating. Burial followed at Cedar Lawn Cemetery in East Hampton.

The family has suggested memorial donations for the East Hampton Library, 152 Main Street, East Hampton 11937, the Springs Library, P.O. Box 1860, East Hampton 11937, or the Springs Presbyterian Church, 105 Old Stone Highway, East Hampton 11937.