Aspen is the home rule city that is the province seat and the most crowded region of Pitkin County, Colorado, USA. Aspen, in Colorado’s Rocky Mountains, is a year-round tourist site for outdoor amusement. Settled in the heart of the White River National Forest and encircled by the peaks of the Elk Mountains, Aspen is famous as a ski destination. Four ski mountains make up the territory. Aspen Mountain locally referred to as Ajax, rises up straight from downtown, bringing a whole new connotation to ski-in/ski-out. Buttermilk Mountain, habitat of the Aspen X Games, is a kids' and beginners' heaven. Aspen Highlands boasts the renowned Highland Bowl, and Snowmass offers the biggest acreage and variety by having something for everyone. Popular outdoor activities include cross-country skiing and snowshoeing, fly-fishing, hot-air ballooning, hiking, biking and even horseback tours.