Effigy << EHF uh jee >> Mounds National Monument is in northeastern Iowa, 3 miles (5 kilometers) north of Marquette. It contains more than 200 prehistoric mounds built by early Indian peoples known today as mound builders. Some of the mounds are hundreds of feet long and were built in the form of animals. The monument was established in 1949. For the monument’s area, see National Park System (table: National monuments).