1964 Map of Weminuche Pass

About this map

The Continental Divide defines the spine of this mid-1960s survey, marking the high-altitude boundary between the San Juan National Forest and the upper reaches of the Rio Grande drainage. This high-country landscape is characterized by the massive Rio Grande Reservoir, where a spillway regulates the water levels near the Thirtymile Campground. Historic movement through these passes is evident in the Ruins at Stage Station Flat and the presence of the Lohr Ditch and Fuchs Ditch, which redirect high-mountain runoff. From the peaks of Simpson Mountain to the depths of Snowslide Canyon, the map traces a network of pack trails and stock driveways used for seasonal grazing in areas like Horse Thief Pasture. This document captures the wilderness character of the San Juan Mountains before later developments altered the backcountry access routes.