Bluffton, originally known as Shannon, is a village in Allen and Hancock counties in the U.S. state of Ohio. The population was 3,967 at the 2…Bluffton, originally known as Shannon, is a village in Allen and Hancock counties in the U.S. state of Ohio. The population was 3,967 at the 2020 census. Bluffton is home to Bluffton University, a four-year educational institution affiliated with Mennonite Church USA. Bluffton is served by the Bluffton general aviation airport. Bluffton participates in the Tree City USA program.