William Lathrop (April 17, 1825 – November 19, 1907) was a U.S. Representative from Illinois.

He moved to Knoxville, Illinois, and was admitted to the bar in 1850.

He settled in Rockford, Illinois, in 1851 and practiced his profession.

He resumed the practice of law in Rockford, Illinois, where he died November 19, 1907.

This article incorporates public domain material from the Biographical Directory of the United States Congress