Montrose is in the south end of the Uncompahgre valley, and is built on the Uncompahgre River, which runs to the north, where 60 miles further its waters will join the Colorado River. It is surrounded by, to the north, the widening Uncompagre Valley and the Grand Mesa, to the east, the Black Canyon of the Gunnison National Park, to the south, the San Juan Mountains, and to the west the Uncompahgre Plateau. The valley is arid, and is only arable due to the water from the Gunnison Tunnel.