Wausau (wôˈsô) [key], city (1990 pop. 37,060), seat of Marathon co., central Wis., on the Wisconsin River; settled 1839, inc. 1872. It is an industrial, commercial, insurance, and agricultural city in the heart of Wisconsin's dairy region. Its many manufactures include wood and plastic products, electric motors, knives, machinery, and steel. Wausau is also the headquarters of a state project that stores and then sells river water for local industrial use. Nearby Rib Mountain State Park attracts tourists.