[4][5][6] In 1804, the Lewis and Clark Expedition stayed for a time with a band of Wičhíyena Sioux on the Vermillion River in modern-day South Dakota.

[7] Lewis wrote in his journal that the Little People were "deavals" (devils) with very large heads, about 18 inches (46 cm) high, and very alert to any intrusions into their territory.

[10] Due to extensive damming of the Missouri River, Spirit Mound is one of the few places which historians can identify as precisely a spot upon which Lewis and Clark stood.

[14] More than 20 buildings, a feedlot, soybean fields, cornfields, several roads, 1,500 non-native trees, and 5 miles (8.0 km) of fence dotted the site.

[18] On July 29, 2001, Senator Tim Johnson presented a symbolic check for $600,000 for the purchase of Spirit Mound and the surrounding land.