Thirtynine Mile Mountain

Thirtynine Mile Mountain is a 11,548 foot (3,523 meter) summit located within Pike National Forest in the South Park area. The peak displays distinctive volcanic conglomerate rock formations that are visible along the ridge and slopes as you climb toward the top.

The mountain sits within the Thirtynine Mile volcanic field, which contains remnants of the Guffey Volcano that ended its activity around 30 million years ago. This volcanic landscape records an important chapter in the geological formation of the South Park region.

The summit ranks as the 76th most prominent peak in Colorado, drawing geologists and researchers interested in studying volcanic formations.

The mountain can be accessed from nearby towns of Hartsel and Guffey via Forest Service roads that branch into the Pike National Forest. Several campgrounds around Lake George provide base options if you want to spend time exploring the area and surrounding peaks.

From the eastern ridge you can see both the Sangre de Cristo Mountains and Pikes Peak on clear days, making this a natural vantage point across the South Park landscape. This dual view across the valley is one of the defining visual features from the summit.

Location: Colorado

GPS coordinates: 38.83222,-105.55500

Latest update: December 14, 2025 11:00