Turkey River Mounds State Preserve is a 62-acre area containing a large complex of ancient Indian mounds on a spectacular narrow ridge overlooking the confluence of the Turkey River and the Mississippi River. It is located 4.5 miles southeast of Guttenberg in Clayton County. The first exploratory survey of the mounds was conducted in 1885. The site was revisited by famous Iowa archaeologist Ellison Orr in the early 1930s. The property was purchased by Dubuque citizens in 1934 and given to the Iowa Conservation Commission in 1940. Later archaeological surveys were conducted in 1964 and 1973. The area was dedicated as an archaeological, geological, and biological state preserve in 1968. It was also placed on the National Register of Historic Places in 1990.