Jämsä (in the local dialect, "Jämpsä") is a town and municipality in Central Finland. It is 223 km from Helsinki, and 58 km from Jyväskylä. There were about 22,125 people living there in January 2014. Jämsä municipality was established in 1866. It is next to the municipalities of Juupajoki, Jyväskylä, Keuruu, Kuhmoinen, Luhanka, Mänttä-Vilppula, Orivesi and Petäjävesi. Isojärvi National Park, a popular hiking place, is near to Jämsä.