The majority of the Sierra Blanca range is within the Lincoln National Forest, and part of this is protected as the White Mountain Wilderness Area.

Much of the southern half of the range, including the summit of Sierra Blanca Peak, is within the Mescalero Apache Indian Reservation.

[5] Sierra Blanca is a massive complex of volcanic rocks, including pyroclastic materials, lava flows, and intrusions.

Most of the eruptions produced voluminous lava flows and breccias, with numerous intrusive dikes emplaced throughout the complex.

[7] Between 2007 and 2014, the Sierra Blanca complex was geologically mapped, and the following stratigraphy was adopted:[8] These rest on the Sanders Canyon Formation, an Eocene sedimentary rock unit.

The Three Rivers Stock, which underlies Sierra Blanca Peak itself, is the largest of these and consists of multiple intrusions, and is composed mostly of syenite to alkali feldspar granite.