The horses and mules that the garrison depended on for mobility required large quantities of feed, and the forage available near the fort was limited and contested.

Warriors who could run off the garrison’s livestock — or kill animals that were grazing outside the walls — degraded the post’s military capability without requiring a direct engagement.

Fort C.F.

Smith, the farthest north of the three posts, was even more isolated.

It was roughly 91 miles from Fort Phil Kearny, which meant that supply runs from the south had to travel more than 260 miles from Fort Laramie before reaching the northernmost post.

The garrison there was small and dependent on seasonal supply runs that could be cut off by weather, by attacks on the trail, or by the combination of both.