Wabasha is a city in Wabasha County, Minnesota, USA. It is also the county seat.The population was 2,495 in 2013. Wabasha is located in southeastern Minnesota on the Mississippi River. Established in 1830, Wabasha is the oldest town in Minnesota. It is also the oldest continuously occupied city in the upper Mississippi River valley. Wabasha is named after chief Wa-pa-shaw of the Sioux Nation.