National monument, southwestern Minnesota, U.S. Established in 1937, it has an area of 282 acres (114 hectares) and contains quarries of a reddish-coloured stone that was used by the Plains Indians to make ceremonial peace pipes.
The stone is reserved for use by the Indians, who quarry it under special permits from the National Park Service. Henry Wadsworth Longfellow popularized the quarries in "The Song of Hiawatha."