The U.S. Army built Fort Phil Kearny in the foothills of Wyoming's Bighorn Mountains in 1866 to protect travelers on the Bozeman Trail headed to Montana's gold fields. The need for this protection arose because the Bozeman Trail cut through the heart of the last bountiful hunting grounds of the Lakotas, Northern Cheyennes, and Northern Arapahos. The incursion by gold seekers led to direct competition with the allied tribes for food and supplies, and...