William E. Mason (July 7, 1850-June 16, 1921) was a Congressman and U.S. Senators from Illinois.
Mason was born in Franklinville, New York. His family moved ti Bentensport, Iowa when he was 8. He attended Birmingham College. After graduating, he taught at Bentonsport Academy, which he had previously attended. After studying law, he moved to Chicago in 1872 and was admitted to the bar.
Mason was elected to Congress in 1887 and again two years later. Following his defeat in 1890, he returned to law practice in Chicago in 1891, but was elected to the U.S. Senate in 1897. After one term, he returned to Chicago. He served three more terms in the House from 1917 until his death. He is buried in Oakwood Cemetery in Waukegan, Illinois.
Preceded by: John McAuley Palmer Class 3 U.S. Senator from Illinois 1897-1903 Succeeded by: Albert J. Hopkins