Jasper is a city in Hamilton County, Florida, United States. The population was 4,546 at the 2010 census, up from 1,780 at the 2000 census. It is the county seat of Hamilton County. The Old Hamilton County Jail and the United Methodist Church in Jasper are on the National Register of Historic Places. One of the largest industries is phosphate mining. The median income for a household in the city was $19,018.