The town of Telluride is the county seat and most populous town of San Miguel County in the southwestern portion of the U.S. state of Colorado. The town is a former silver mining camp on the San Miguel River in the western San Juan Mountains. The Telluride Historic District, which includes a significant portion of the town, is listed on the National Register of Historic Places and is also one of Colorado's 20 National Historic Landmarks. The town population was 2,221 in the 2000 United States Census. Telluride is located at an elevation of 8,750 feet in an isolated spot in Southwest Colorado. From the west, Colorado Route 145 is the most common way into Telluride, however there are two alternate passes to enter the town as well. Imogene Pass is the more forgiving of the two passes, though it still requires 4x4 experience and should not be taken lightly. Black Bear Pass is noted to be Colorados most dangerous pass. It is passable only in one direction because of a treacherous stair step section.