Bluffton is a city in and the county seat of Wells County, Indiana, United States. The population was 10,308 at the 2020 census, up from 9,89…Bluffton is a city in and the county seat of Wells County, Indiana, United States. The population was 10,308 at the 2020 census, up from 9,897 at the 2010 census. Bluffton is nicknamed the "Parlor City" for its history of having some of the first clean paved streets in the area during the time of the Indiana gas boom.