Fort Sarpy tells the story of the American Fur Company's most dangerous post. The fort was built on the Yellowstone River in 1850 for the trade with the Crows. At this time, the tribe waslocated in a triangle between the Tongue and the Bighorn River, with its northern boundary generally the Musselshell River. In 1850, the Crows were a small tribe. Because of strong and numerous enemies - the Sioux, the Cheyenne and the Arapahoe - the Crows had not had general access to the white man's trade goods unless they traveled out of their country, always a dangerous situation. Piercing this ring of foes and establishing a post for them was a precarious enterprise. The job was undertaken by Robert Meldrum, a man who lived with and knew the Crows like no other white man. Caleb Shaw, the young man who goes with him to erect the post, becomes his able assistant and a full-fledged mountain man. This book is about Fort Sarpy, the American Fur Company men who dared to build it in the wilderness, and the Crow tribe, who owe their existence to its creation.