Mercer is a town in southern Iron County, Wisconsin, United States. The population was 1,732 at the 2000 census. The census-designated place of Mercer and the unincorporated communities of Carter and Manitowish are located within the town.
Mercer identifies itself as the "Loon Capital of the World" in order to promote tourism. This is based on a wildlife study that found Mercer had the highest concentration of common loons in the world. In front of the Mercer Chamber of Commerce's information center, there is a 16-foot (4.9 m), 2,000-pound (910 kg) statue named "Claire de Loon." Mercer also hosts an annual "Loon Day" festival, which features a large arts and crafts fair, live music and a loon calling contest.
According to the United States Census Bureau, the town has a total area of 184.8 square miles (478.5 km²), of which, 168.0 square miles (435.2 km²) of it is land and 16.7 square miles (43.3 km²) of it (9.05%) is water.