R. Harrison (Dick) Sothoron, 71, who died Sunday when fire destroyed the interior of his home in Upper Marlboro, was a retired title officer and had been a member of the Upper Marlboro Town Commission for 30 years.

He had served as the commission's secretary-treasurer and in other capacities.A resident of Upper Marlboro since 1941, he was an air-raid warden for the town during World War II, a member of the Upper Marlboro Centennial Committee in 1976 and a justice of the peace for Prince George's County.

Mr. Sothoron was a 37-year member and former secretary-treasurer of the Marlboro Lions Club. He was past president of the Southern Maryland Society and was active in the Maryland Municipal League. He had served on the vestry of Trinity Episcopal Church in Upper Marlboro for many years.

In 1966 the town honored him with a "Dick Sothoron Day."

He was born in Charlotte Hall, Md., and attended Charlotte Hall Junior College. He worked in Brooklyn, N.Y., for a metal hose and tubing company during the 1930s.

After moving to Upper Marlboro, Mr. Sothoron worked for the U.S. Post Office there. He then became a title abstractor for District Lawyers in Washington in 1943. Except for a period when he worked for the Maryland Home and Title Co., he remained with District Lawyers through 1958, when it merged with the District Realty Title Insurance Co. He retired from the latter in 1977.

His wife of 43 years, the former Jean Dukeshire, died in 1977.

Survivors include his daughter, Carol Peddicord of Washington; a son, Richard H. Jr., of University Park; a sister, Julia S. Buddington of Hyattsville, and a brother, retired Army Col. Norwood S., of Lexington Park, Md.