Oliver Ellsworth, mayor of Piedmont for 25 years, died at a local hopsital yesterday after a heart attack.

Ellsworth, veteran San Francisco and Oakland attorney, was a member of the Piedmont Lodge of Masons, Scottish Rite bodies, Shriners, Diablo Country Club, Commonwealth Club and Beta Theat Pi.

He is survived by his widow, Mrs. Lillian Ellsworth; a daughter, Mrs. E.A. Wilson of San Mateo; a sister and two brothers.