In 1861 the land now designated as The Keep was offered to settlers in quarter-section parcels. Each homesteader had but to build a house, cultivate the land, and live on the property. Then after five years, the new Colorado Territory families were allowed to purchase their land from the federal government for $1.25 per acre. The land remained largely open as it is now, with pasture cattle and wildlife as the primary inhabitants.

When Tweet Kimball took over the land, she ran a herd of Santa Gertrudis cattle, a breed common in hot, dry climates, but new then to Colorado. The cattle flourished for 50 years on the Cherokee Ranch, and a few remain for educational and agricultural exhibits. The land stands today as it did then, thick with native grasses, Gambel Oak, Juniper, Douglas Fir, Ponderosa Pine and endless wildflowers. In 1996, The Cherokee ranch and Castle Foundation removed the development rights on 31,000 acres of the ranch property, ensuring this land will remain protected and conserved as open space forever.