Retired Army Brig. Gen. John G. Hill, 80, a combat veteran of both World Wars and the Korean conflict and a former resident of Arlington, died Saturday at a hospital in Savannah, Ga. He had a heart ailment.

Gen. Hill was stationed at the Pentagon when he retired from the Army in 1954. He then became an operations analyst with the Research Analysis Corporation here, doing research for the Defense Department. He retired a second time in 1965. He moved to Hilton Head Island, S.C., a year ago.

He was born in Kansas. During World War I, he enlisted in the Army and participated in four campaigns in France with the 35th Infantry Division. He was discharged at the end of the war and a year later entered the U.S. Military Academy at West Point, where he graduated in 1924. His assignments prior to World War II included duty in the Panama Canal Zone.

During World War II, he served in Europe, helping to plan the Normandy landings and then taking part in the major campaigns in France and Germany. After the war, he was with the European Command of the Army, returning to this country in 1950. He was sent to Korea with the 2nd Infantry Division that year and saw action in the heavy fighting along the Naktong River. He returned to Korea in 1953 as commander of the 40th Infantry Division and remained there until several months before his retirement here.

Gen. Hill's decorations included the Distinguished Service Medal, three Legions of Merit, the Bronze Star Medal and a number of foreign awards.

His first wife, Selma Lawes Hill, died in 1969.

He is survived by his wife, Sarah, of Hilton Head Island; a son, retired Army Maj. Gen. John G. Jr. of Austin, Tex.; a daughter, Jocelyn Dickson of Potomac; five stepchildren; four brothers; three sisters; seven grandchildren and 12 stepgrandchildren.

The family suggests that expressions of sympathy be in the form of contributions to Grace Episcopal Church in Alexandria, or to a charity of one's choice.