IRENE GERHARDT JACKSON, 95, the widow of Supreme Court Justice Robert H. Jackson, died July 18 at the Bethesda Retirement and Nursing Home of complications resulting from a stroke she suffered in December 1982.

Mrs. Jackson came to Washington in 1934 when her husband was named general counsel of the old Bureau of Internal Revenue. She served as official hostess for him when he was solicitor general, attorney general and associate justice of the Supreme Court.

She was a former board member of the Visiting Nurse Society and the Animal Rescue League. During World War II she was a Red Cross Grey Lady and an air raid warden. She was also a member of the Sulgrave Club.

During the 1940s and early 1950s, Mrs. Jackson lived at Hickory Hill in McLean. After Justice Jackson's death in 1954, the property was sold to John F. Kennedy, who was then a senator, and subsequently to his brother, Robert F. Kennedy. Afterward, Mrs. Jackson lived in Washington.

A native of Kingston, N.Y., Mrs. Jackson was an enthusiastic horsewoman in Jamestown, N.Y., before moving to Washington.

Survivors include one son, William E. Jackson of New York City; one daughter, Mary L. Craighill of Washington; eight grandchildren, and four great-grandchildren.