Aspen is a town, city, and ski resort community in Pitkin County, Colorado, United States. It is the county seat of Pitkin County and is in a remote area of the Rocky Mountains' Sawatch Range, along the Roaring Fork River at an elevation just below 8,000 feet (2,400 m) above sea level on the Western Slope, 11 miles (18 km) west of the Continental Divide. As of the 2010 census, there were 6,658 permanent residents.
Founded as a mining camp during the Colorado Silver Boom and named because of the abundance of aspen trees in the area, the city boomed during the 1880s, its first decade of existence. That early era ended when the Panic of 1893 led to a collapse in the silver market, and the city began a half-century known as "the quiet years" during which its population steadily declined, reaching a nadir of less than a thousand by 1930. Aspen's fortunes reversed in the mid-20th century when neighboring Aspen Mountain was developed into a ski resort, and industrialist Walter Paepcke bought many properties in town and redeveloped them. Today it is home to three renowned institutions, two of which Paepcke helped found, that have international importance: the Aspen Music Festival and School, the Aspen Institute, and the Aspen Center for Physics.