The City of Fort Collins is the Home Rule Municipality that is the county seat and the most populous municipality of Larimer County, Colorado, United States. Fort Collins is the principal city of the Fort Collins, CO Metropolitan Statistical Area and is a major city of the Front Range Urban Corridor. Situated on the Cache La Poudre River along the Colorado Front Range, Fort Collins is located 56 mi (90 km) north of the Colorado State Capitol in Denver. With a 2019 estimated population of 170,243, it is the fourth most populous city in Colorado after Denver, Colorado Springs, and Aurora. Fort Collins is a midsize college city, home to Colorado State University and Front Range Community College's Larimer campus.
Fort Collins was founded as a military outpost of the United States Army in 1864. It succeeded a previous encampment, known as Camp Collins, on the Cache La Poudre River, near what is known today as Laporte. Camp Collins was erected during the Indian wars of the mid-1860s to protect the Overland mail route that had been recently relocated through the region. Travelers crossing the county on the Overland Trail would camp there, but a flood destroyed the camp in June 1864. Afterward, the commander of the fort wrote to the commandant of Fort Laramie in southeast Wyoming, Colonel William O. Collins, suggesting that a site several miles farther down the river would make a good location for the fort.