Frederick Olen Mercer (March 11, 1901 – April 3, 1966) was a United States district judge of the United States District Court for the Southern District of Illinois.
Born in Vermont, Illinois, Mercer received a Bachelor of Laws from the University of Illinois College of Law in 1924.
He was an assistant state's attorney of Fulton County, Illinois from 1924 to 1926.
[1] Mercer was nominated by President Dwight D. Eisenhower on May 17, 1956, to a seat on the United States District Court for the Southern District of Illinois vacated by Judge J. Leroy Adair.
Mercer served in that capacity until his death on April 3, 1966.