Julesburg, Colorado, visible to the southwest, was established as a road ranche, trading post, and stage station in 1859. Located near the junction of several overland routes, Old Julesburg became an important transportation and military center during the 1860s. On January 7, 1865, more than 500 Sioux and Cheyenne attacked Julesburg in revenge for the Sand Creek Massacre of November 29, 1864. The small military force at nearby Camp Rankin, established in 1864, was unable to prevent the Indians from burning the settlement and killing 18 defenders. Julesburg was rebuilt on a new site. The military post was enlarged and later renamed Fort Sedgwick.
Until it was abandoned in 1871, Fort Sedgwick was a focal point for military activities in the region. During construction of the Union Pacific across western Nebraska in 1867, troops protected the construction workers from the threat of Indian attack. Julesburg was rebuilt near the railroad. The town lasted less than a year and was noted for vice and violence. The fourth and present Julesburg was platted as Denver Junction in 1884. It was renamed Julesburg when it was incorporated two years later.