Colorado was named after the Colorado River, which in turn was named for its reddish hue from the silt it carries from the mountains. Colorado is Spanish for "colored red." In 1861, the population of the unnamed territory had risen high enough from the Pike's Peak gold rush that Congress combined parts of Nebraska, Kansas, Utah and New Mexico to create Colorado.
Although the United States acquired the territory in 1848, the land remained virtually unpopulated by white settlers, who were content to leave it to various Native American nations. However, in the summer of 1858, a band of prospectors near what would later become Denver discovered flecks of gold in their pans; by 1859, approximately 50,000 settlers had arrived to chase after gold. Wherever large amounts of gold were found, cities appeared, Denver becoming the miners' supply town. While miners generally did not plan on staying in Colorado, they sought to protect their property rights and formed basic governments and miners' courts that provided some semblance of law and order, though they lacked legal foundation. Eventually, when it became clear that these informal mining efforts were being replaced by efficient and permanent mining operations, settlers realized the territory's potential to form a new state.