San Juan National Forest spans more than 1,878,846 acres in western Colorado across the southern San Juan Mountains west of the Continental Divide. Created by President Theodore Roosevelt on June 3, 1905, it forms part of one of Colorado’s largest high-country public landscapes alongside the Uncompahgre and Rio Grande national forests. Named for the San Juan River, its lands include major alpine backcountry, the Weminuche, South San Juan, Lizard Head, and Hermosa Creek wilderness areas, and the Piedra Area. The Durango and Silverton Narrow Gauge Railroad passes through its mountains, and in 2012 part of the forest became Chimney Rock National Monument.