Jasper is a city in Dubois County, Indiana, United States. The population was 15,038 at the 2010 census. The city has been the county seat of Dubois County since 1830, succeeding Portersville. In 1970, the school system of Ireland, a hamlet west of Jasper along State Route 56, was consolidated into that of Jasper. On November 4, 2007, Dubois County returned to the Eastern Time Zone, after having moved to the Central Time Zone the previous year.