William Hartzell (February 20, 1837 – August 14, 1903) was a U.S. Representative from Illinois. Hartzell was born in Canton, Ohio. He moved with his parents to Danville, Illinois, in 1840. In 1844 the Hartzells moved to Mexico, where William Hartzell remained until 1853. In 1853 Hartzell returned to the United States and moved to Randolph County, Illinois. He then went to study law at McKendree College. Hartzell graduated from McKendree in 1859.He settled in Chester, Illinois. He was admitted to the bar in 1864 and commenced practice in Chester, Illinois.