The Western Slope is generally drained by the Colorado River and its tributaries. Notable to the south are the San Juan Mountains, an extremely rugged mountain range, and to the west of the San Juans, the Colorado Plateau, a high desert bordering Southern Utah. Grand Junction is the largest city on the Western Slope. Grand Junction is served by Interstate Highway I-70. To the southeast of Grand Junction is Grand Mesa, a large flat-topped desert mountain. Further east are the ski resorts of Aspen, Vail, Crested Butte, and Steamboat Springs. The northwestern corner of Colorado bordering Northern Utah and Western Wyoming is mostly sparsely populated rangeland.