What is now Hornell was first settled in 1790 under the name "Upper Canisteo", to distinguish it from the community of Canisteo, then known as "Lower Canisteo". The family of Benjamin Crosby were the first settlers in what is now Hornell. The area was incorporated as a town in 1820, as "Hornellsville." The name comes from early settler George Hornell Jr, who built the first gristmill here.

The 2011 Saint Patrick's Day parade in Hornell.
The City of Hornell was chartered in 1888 as the "City of Hornellsville," (having been first organized as the "Village of Hornellsville" in 1852). The name was changed to Hornell in 1906.