Dayton M. Harrington, 61, a lawyer in Washington since the late 1940s and a former commander of the District of Columbia Amvets, died Saturday at his home in Washington. He had a heart ailment.

Mr. Harrington was born in Peoria, Ill. He grew up in Keokuk, Iowa, and later graduated from the University of Iowa. He came to Washington in the late 1930s as a student at George Washington University law school and earned his degree there is 1942.

He served in the Army during World War II and then returned here to open a law practice. He interrupted his practice to spend two years with the War Crimes Commission in the Philippines. Since the late 1940s, he had been in practice here with the firm of Harrington and Graham.

Mr. Harrington also served on the D.C. board of appeals and review, which has jurisdiction over licensing matters, from 1960 to 1963.

He was active in veterans groups for many years and was elected to a term as commander of the D.C. Amvets in 1960. He participated in alumni affairs of the George Washington University law school. He was a member of the parish of St. Joseph's Catholic Church in Washington.

Survivors include his mother, Lillian Eller, of Keokuk; a brother, Joseph Harrington, of McLean, and two sisters, Margaret Griffey, of Keokuk, and Mary Kenzie, of Chicago.

The family suggests that expressions of sympathy be in the form of contributions to St. Joseph's Catholic Church, Washington. CAPTION: Picture, DAYTON M. HARRINGTON