Sweet Grass Hills

The geologic formation appearing in the distance to the left of the train is known as the Sweet Grass Hills. Though on a clear day they may appear to be fairly close, they are actually nearly 30 miles north, just on the US side of the Canadian Border. The tallest, West Butte, is almost 7,000 feet high, while Gold Butte and East Butte are each over 6,500 feet high.

This formation is more than just “hills;” they are ancient volcanic boils. The “hills” were not created by volcanic eruptions, but by molten igneous rock being forced up from below and then solidifying. Geologists think this happened between 34 and 56 million years ago. Then, because of uplift and erosion, the overlying surface has disappeared. The hills are now covered in wavy grass, and also, because of their higher elevation, are home to groves of Douglas fir trees and some plant and animal species not found on the prairie here below. Many Native American tribes in Montana consider the Sweet Grass Hills to be sacred.