In the summer of 1837, Henry Fraeb and Peter Sarpy arrived at a location on the South Platte River a few miles north of present-day Fort Lupton. They arrived with $10,909.75 worth of goods for trade with the Cheyenne and Arapaho who frequented the area. Upon arrival, Fraeb and Sarpy began construction of a stockade adobe trade fort, which they christened Fort Jackson. Along with Fort Vasquez (established 1835), Fort Lupton (1837), and Fort St. Vrain (1837), Fort Jackson was part of an intense but short-lived trading locus along a thirteen-mile stretch of the South Platte River.
Along with the other forts, Fort Jackson was built near the wintering grounds of the Cheyenne and Arapaho so it could easily take in bison robes produced by the Native Americans after their summer hunts. Although no records exist of its size, based on similarities between it and other contemporary South Platte forts, Fort Jackson was likely around 100 square feet with high walls and bastions.
Pratte, Chouteau & Company of St. Louis financed the goods brought by Fraeb and Sarpy, who hoped to make inroads into the burgeoning regional trade. During the trade of 1837–38, inventory records indicate that Fort Jackson took in 2,920 robes from adult bison and calves worth $9,715.87 ($249,125 today). Despite these numbers, the post was short-lived and was transferred in October of 1838 to Bent, St. Vrain & Company, which operated Fort St. Vrain. Following the transfer of the post inventory, Fort Jackson was demolished. It is likely that financial difficulties brought on by the Panic of 1837 were partly responsible for Fort Jackson’s closing. With its demise and the closings of Fort Vasquez and Fort Lupton in 1842, the trading locus on the South Platte ceased to be economically important. However, the story of Fort Jackson, along with the other nearby posts, is an important part of the fur trade history of Colorado.
