National Monuments Established by Harry S. Truman via the Antiquities Act:
April 12, 1945, to January 20, 1953
Effigy Mounds, IA, Proclamation No. 2860, 64 Stat. a371 (October 25, 1949)
Area reserved: “1,204.39 acres, more or less.”
Truman’s proclamation describes the federal lands (“1,000 acres”), which already had been conveyed “as a donation for national-monument purposes” to the United States, and the state lands (“204.39 acres”), which the proclamation text suggests were to be added “for national-monument purposes in the near future.” However, Section 2 of the Antiquities Act states that national monuments can only be established “upon the lands owned or controlled by the Government of the United States,” so the more accurate figure would appear to be 1000 acres.