The City of Aspen is the home rule municipality that is the county seat and the most populous municipality of Pitkin County, Colorado, United States. The city population was 7,004 at the 2020 United States Census. Aspen is in a remote area of the Rocky Mountains' Sawatch Range and Elk Mountains, along the Roaring Fork River at an elevation just below 8,000 feet above sea level on the Western Slope, 11 miles west of the Continental Divide. Aspen is now a part of the Glenwood Springs, CO Micropolitan Statistical Area.
Founded as a mining camp during the Colorado Silver Boom and later named Aspen for the abundance of aspen trees in the area, the city boomed during the 1880s, its first decade. The boom ended when the Panic of 1893 led to a collapse of the silver market. For the next half-century, known as "the quiet years", the population steadily declined, reaching a nadir of fewer than 1000 by 1930. Aspen's fortunes recovered in the mid-20th century when neighboring Aspen Mountain was developed into a ski resort, and industrialist Walter Paepcke bought many properties in the city in the 1950s and redeveloped them.