State Trunk Highway 161 (often called Highway 161, STH-161 or WIS 161) is a 22.42-mile (36.08 km) state highway in Portage and Waupaca counties in the central part of the US state of Wisconsin. It runs in east–west from US Highway 10 (US 10) northwest of Amherst Junction via Iola to WIS 22/WIS 110 just west of Symco.