Carter Henry Harrison, Sr. (February 15, 1825 – October 28, 1893) was an American politician who served as mayor ofChicago, Illinois from 1879 until 1887; he was subsequently elected to a fifth term in 1893 but was assassinated before completing his term. He previously served two terms in the United States House of Representatives. Harrison was the first cousin twice removed of President William Henry Harrison.

Born near Lexington, Kentucky to Carter Henry Harrison II and Caroline Russell,^[1] he was only a few months old when his father died. He was educated by private tutors, and was graduated from Yale College in 1845 as a member of Scroll and Key. Following graduation, he traveled and studied in Europe from 1851 to 1853 before entering Transylvania College in Lexington, where he earned a law degree in 1855. He was admitted to the bar in 1855 and commenced practice in Chicago; Harrison came to Chicago because he saw it as a land of opportunity.

Harrison ran an unsuccessful campaign in 1872 for election to the Forty-third Congress. Beginning in 1874, he served as a member of the board of commissioners of Cook County. He was elected as a Democrat to the Forty-fourth and Forty-fifthCongresses, and delegate to the 1880 and 1884 Democratic National Conventions.