The Creation and Evolution of Effigy Mounds National Monument

On October 25, 1949, President Harry S. Truman signed a presidential proclamation that created Effigy Mounds National Monument (NM). At the time, the 1,000-acre monument consisted of today’s South Unit, which includes the Marching Bear Group of mounds, and today’s North Unit, which includes the Little and Great Bear Groups of mounds. The dividing line was the Yellow River, which bisects the monument as it flows east into the Mississippi River. The monument that exists in 2022, though, is larger than when first established.

In 1951–1952, following President Truman’s proclamation, the National Park Service (NPS) assumed management of an additional 204 acres the state of Iowa transferred to the Federal government. Three years later, in 1955, the Des Moines Founders Garden Club donated an additional 40 acres. These 40 acres located south of the Yellow River contained Founder's Pond. Further expansion occurred in 1961, when Congress authorized acquisition of approximately 100 acres called the Ferguson tract, an acquision finalized in 1975. In the meantime, transfer of the roughly 138-acre Sny Magill property from another federal agency in 1962, also authorized in the 1961 legislation, doubled the number of mounds within the monument. The most recent expansion took place in 1999; that year the Iowa Natural Heritage Foundation purchased 1,045 acres and transferred it to the NPS. Known as the Heritage Addition, this property increased the total size of the monument to 2,526 acres. Because of these actions, Effigy Mounds NM today preserves more than 200 known mound sites, including 31 bear and bird effigies—the largest known concentration of surviving mounds in the United States.

As was common in the early and mid 1900s, President Truman established the monument because of “great scientific interest” in the mounds and what they might reveal about the “prehistoric American Indians” who built them between 800 and 2500 years ago. Throughout the 1950s and 1960s, consequently, the NPS used archeological excavations to investigate the effigy and burial mounds found within the monument. Because such excavations reduced or destroyed the burial and ceremonial mounds’ value as scientific objects, some people questioned the wisdom and benefits of excavating them. In 1959, Effigy Mounds NM established a policy that prohibited further destructive investigations of the mounds; only nondestructive testing methods would be permitted in the future. By the 1970s, the emphasis on archeological field investigations had shifted toward preserving and interpreting the story of the peoples who built the mounds.

This shift continued during the 1980s. Rather than emphasize and privilege only the "scientific" perspective, the NPS started to consider the mounds and the surrounding landscape from a humanistic perspective. While the "science" of the mounds still mattered, Effigy Mounds NM began to recognize and interpret what modern American Indians considered as a "sacred landscape." Congress’ passage of the Native American Graves Protection and Repatriation Act (NAGPRA) in 1990 accelerated this change, initiating a new chapter in the monument’s history. This act requires Federal agencies and museums that hold Native American human remains and cultural items to consult with lineal descendants and culturally affiliated Indian tribes. Consultation and dialog that began in the 1990s has led to a deeper understanding and revitalization of the long-overlooked connections between the monument, affiliated tribes, and the living descendants of the Native American peoples who lived and thrived on this land and built the mounds. It’s an evolution still in process.

Last updated: November 28, 2022

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