John P. Fort, 66, a psychiatrist who had served on the staff of Chestnut Lodge Hospital psychiatric facility in Rockville since 1955, died June 17 at Shady Grove Adventist Hospital after a heart attack.

At his death, Dr. Fort was Chestnut Lodge's associate medical director. From 1965 until earlier this year, he had been the hospital's clinical director.

A resident of Washington, he was born in Chattanooga, Tenn. He graduated from the University of the South in Sewanee, Tenn., and received his medical degree from Tulane University.

He was a former president of the Central Neuropsychiatric Hospital Association, a trustee of the National Association of Private Psychiatric Hospitals and a member of the Chestnut Lodge Board of Trustees.

He was editor emeritus of the journal Psychiatric Hospital, and had written articles for professional journals.

Dr. Fort was a member of the Washington School of Psychiatry, the International Advisory Council of Addictions, the American Group Psychotherapy Association, the Board of Directors of the Washington Council on Alcoholism, the Montgomery County Medical Society, the American Psychiatric Association and the Washington Psychiatric Society.

His marriage to Ruth Fort ended in divorce.

Survivors include his wife, Denise C. Fort of Washington; three children of his first marriage, Arthur Fort of Boston, Bruce Fort of Santa Fe, N.M., and Denise Fort of San Francisco; and two brothers, Keith Fort of Washington and James F. Fort of Alexandria.