| William St. Onge | |
| State: | Connecticut |
| Term Start: | January 3, 1963 |
| Term End: | May 1, 1970 |
| Predecessor: | Horace Seely-Brown Jr. |
| Successor: | Robert H. Steele |
| Birth Date: | 9 October 1914 |
| Birth Place: | Putnam, Connecticut, U.S. |
| Death Place: | Groton, Connecticut, U.S |
| Education: | Tufts University University of Connecticut |
| Serviceyears: | 1942–1945 |
William Leon St. Onge (October 9, 1914 – May 1, 1970) was a United States Representative from Connecticut.
He was born in Putnam, Windham County, Connecticut, and attended the secondary schools of Putnam. He graduated from Tufts University in 1941 and enlisted in the United States Army in 1942, serving in the Army Air Corps in North Africa and Europe, and was discharged as a flight engineer in September 1945. He then attended the University of Connecticut School of Law at Hartford in 1948, and was admitted to the bar in 1948. He commenced the practice of law in Putnam in 1948, becoming judge of the probate court from 1948 to 1962.
He was a member of board of education of Putnam in 1939–1941, and served in the State House of Representatives in 1941–1942. He served as prosecutor of the city court of Putnam from 1949 to 1951, and in 1955 he became judge of the city court of Putnam, serving until 1961. He was chairman and executive director of the redevelopment agency of Putnam, 1956–1958, and was mayor of the city in 1961–1962.
In 1962 he was elected as a Democrat to the Eighty-eighth and to the three succeeding Congresses, serving from January 3, 1963, until his death from a heart attack in Groton, Connecticut in 1970.[1] His body was interred in St. Mary's Cemetery, Putnam. He was succeeded as Representative by Robert H. Steele.