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1991 Map of Porphyry Peak

Name: 1991 Topographic Map of Porphyry Peak
Creator: U.S. Geological Survey
Published: 1991
License: https://creativecommons.org/publicdomain/mark/1.0/

USGS Topo · Published 1991

About this map

Rosenkrance Ranch sits at the southern edge of this high-elevation terrain, where the East Fork Big Lost River meets the Big Lost River. The landscape is dominated by the steep southern ridges of the White Cloud Mountains and the sprawling territory of the Challis National Forest. This 1991 provisional map highlights the vertical complexity of the region, from the prominent Porphyry Peak and Challis Knob to the sheer formation at Castle Rock.

A network of 4WD trails provides the primary access through deep drainages like Castle Rock Canyon and along Boone Creek. The mapping reveals a remote environment focused on natural landmarks and resource management, evidenced by the presence of a Radio Facility and numerous named springs and creeks such as Bartlett Creek and Little Boone Creek. The transition from the plateau of Flat Top to the river valleys below illustrates the significant topographic variation typical of central Idaho's wilderness.