The rockshelter was first inhabited by people of the Archaic through the Middle Ceramic period, generally spanning 3000 BC to 1000 AD.

[5]: 11, 22 The period immediately preceding the first humans coming into Colorado was the Ice Age Summer starting about 16,000 years ago.

Receding and melting glaciers created the Plum and Monument Creeks, the Castle Rock mesas and unburied the Rocky Mountains.

Large mammals, such as the mastodon, mammoth, camels, giant sloths, cheetah, bison antiquus and horses roamed the land.

Late in the Archaic period, about AD 200–500, corn was introduced into the diet and pottery-making became an occupation for storing and caring food.

[5] The Early Ceramic, or Woodland, period began in the Plains about AD 1 with the defining distinction of the creation of cordwrapped pottery, development of settlement areas, and use of smaller projectile points for bow and arrow technology.