Dianne L. MacDonald

Dianne L. MacDonald, a clinical social worker for four decades after graduating from Columbia University, died after a brief illness on Dec. 10 at Stony Brook Southampton Hospital. She was 71 and had been in declining health. 

Ms. MacDonald worked for the East Hampton School District for many years and also had a private practice at home. Jean MacDonald Altz, a cousin, said she had touched a lot of lives and had “a large circle of friends in her beloved Montauk.” 

“She had lived in Manhattan for a while, but she chose to move to Montauk as a year-round resident about 40 years ago because once you’re there, you don’t want to leave,” Ms. Altz said. “She loved the town, loved the beach. She became someone that pretty much stayed put there.”

Ms. MacDonald was born on Aug. 20, 1947, in Ossining, N.Y., the daughter of Martin and Evelyn Petrone MacDonald. She grew up in Thornwood, N.Y., and graduated from Westlake High School there. A brother, Thomas MacDonald, died before her.

She is survived by an uncle, Norman MacDonald of Bronxville, N.Y., and a number of cousins, including Ms. Altz, who lives in Brewster, N.Y. Burial was in a family plot at Kensico Cemetery in Valhalla, N.Y.