Highlighting Spearfish

Crow Peak Trail

Spearfish, SD 57783

Crow Peak is a dominant landmark because of its geological makeup. Billions of years ago, this area was covered by an ocean. Layers of sediment were deposited on the ocean floor, eventually hardening to form limestone and other sedimentary rock layers. Underground molten rock called magma pushed the sedimentary layers upward forming hills. During the uplifting, crevasses within the limestone hills filled with magma. These flows of magma, called intrusions, cooled to form igneous rock. The limestone and other sedimentary rock erodes at a faster rate than the harder igneous rock. As the oceans eceded, the overlying sedimentary rock eroded, exposing the igneous intrusions. Crow Peak and other peaks you can see from the Crow Peak summit, such as Bear Butte, Spearfish Mtn., and Terry Peak, were formed in this manner. Erosion of this igneous rock and the sedimentary rock surrounding these peaks continues to shape the landscape of the Northern Black Hills.
Please use "Flag This Place" to alert us about content that is inappropriate or needs immediate attention. Nothing you submit will be shared with other site visitors.
Explore the free AARP HomeFit Guide

AARP Events for Spearfish

View All AARP Events

image of two AARP membership cards
Only $12 your first year with Automatic Renewal
  • Immediate access to your member benefits
  • Discounts on travel and everyday savings
  • Subscription to AARP The Magazine
  • FREE second membership
Join AARP
Already a member? Renew or Print Card

Contact AARP
in Spearfish