2020 Map of Boulder Chain Lakes

About this map

White Cloud Peaks define the high-elevation landscape of this 2020 survey, where dramatic alpine terrain creates a complex network of glacial cirques and tarns. The area is divided between Challis National Forest and Sawtooth National Forest, highlighting a protected wilderness environment. Prominent summits including Castle Peak, Merriam Peak, and Patterson Peak tower over deep glacial depressions such as Chamberlain Basin and Four Lake Basin. The map reveals the intricate hydrology of the region, specifically the string of tarns known as the Boulder Chain Lakes and the sprawling Big Boulder Lakes system. Historical land management is reflected in features like the Livingston Mill-Castle Divide, while geologic formations such as Serrate Ridge and The Kettles illustrate the powerful impact of past glaciation on the Custer County high country.