1991 Map of Sylvan Lake

About this map

Yellowstone National Park reveals its geothermal and high-elevation character on this 1991 survey, centered on the dramatic ascent to Sylvan Pass. The landscape is defined by hydrothermal activity, most notably at the Brimstone Basin and various other Thermal Areas that dot the terrain. To the south, the map captures a portion of the Southeast Arm Yellowstone Lake, where the Thorofare Trail begins its trek into the interior wilderness.