Clyde R. Carter, 57, a retired farmer in Calvert County who was active in the American Legion, was found dead Thursday in his automobile near the intersection of Maryland Route 4 and Pennsylvania Avenue in Forestville. The Maryland State medical examiner's office said the cause of death was a heart ailment.

Mr. Carter was a lifelong resident of Huntingtown, Md. He was graduated from the old Brooks High School, the Phelps Vocational Institute in Washington and the National Radio Institute. He served in the Army Air Forces during World War II.

He was a farmer in Huntingtown and raised tobacco and cattle. He retired around 1975 for reasons of health.

He was a former commander of the Gray-Ray Post No. 220 of the American Legion in Prince Frederick, Md., and the Calvert County Council of the Legion. He was chef de gare of the Tri-County Voiture Locale No. 456 of the Legion's Forty and Eight society. He was a former district judge advocate and district chaplain and a member of the executive committee of the Maryland department of the Legion.

Mr. Carter also was a Mason and a member of the Kiwanis Club of Calvert County. He was a member of the Mount Hope United Methodist Church in Sunderland, Md., and a director of the Southern Maryland Chapter of the American Heart Association.

Survivors include his wife, Sarah, and a daughter, Claudette C. Brown, both of Huntingtown; a stepson, Irvin Hudson, of Baltimore; four sisters, Thelma Banks, of Washington, Anne Griffith of Upper Marlboro, Wilhelmina Simms, of Temple Hills, and Julia Lacy, of Lanham; two brothers, James, of Huntingtown, and Herman, of Sunderland; three half brothers, Langford and Irving Long, both of Huntingtown, and Wilburn Long, of Washington, and two grandchildren.