Aspen, Colorado, the seat of Pitkin County. It is on the Roaring Fork, a tributary of the Colorado River, about 100 miles (160 km) southwest of Denver. Aspen lies in the Rocky Mountains at an altitude of 7,850 feet (2,393 m). It is a ski center with chair lifts to nearby Ajax Mountain (11,300 feet [3,440 m]). Summer activities include a music festival and seminars of the Aspen Institute.

Aspen was settled by silver miners in 1879 and incorporated as a town in 1886. After 1893 silver mining declined and Aspen became almost a ghost town. Its development as a resort center began in the 1940's.

Population: 5,914.