Dixie Roach Harris, 72, a retired historian with the Department of the Army, died Wednesday at Northern Virginia Doctors Hospital. She had suffered from a heart ailment.

Mrs. Harris came to Washington in 1944 and worked as a historian in the historical section of the office of the chief signal officer from 1945 to 1947.

From 1949 to 1952, she was with the signal corps section of the office of the chief of military history. She then became assistant chief of the signal corps historical office, retiring in 1963. The military history office of the Army is now called the Army Center of Military History.

Mrs. Harris was the coauthor of three volumes that are part of the Army's official history of "United States Army in World War II."

The volumes are "The Signal Corps: The Emergency (to December, 1941)," published in 1956. "The Signal Corps: The Test (December, 1941 to July, 1943), published in 1957, and "The Signal Corps: The Outcome (mid-1943 through 1945)," published in 1966.

Born in Winamac, Ind., Mrs. Harris married the late Ray M. Harris, a lawyer, in 1928 after her marriage she attended Manchester College in Indiana and graduated magna cum laude from Ohio State University.

She studied law in her husband's law office in Dayton, Ohio, and was admitted to the Ohio Bar in 1938. She then practiced law with her husband for four years in Dayton.

From 1942 to 1944, Mrs. Harris was the civilian assistant to the commanding officer of the Dayton Signal Corps Publications Agency at Wright Field.

She came to Washington when her husband joined the federal government here. He held several positions ad was retired head of the patent office of the National Aeronautics and Space Administration at the time of his death last year.

Mrs. Harris, who lived in Arlington, is survived by a sister, Flossie Felker of Winamac.