In early July Lewis and his group arrived back at the Great Falls.
However, they were in Blackfeet territory‚ a group of people noted for not liking others on their land, either other American Indians or European-Americans.
At first the Blackfeet seemed friendly to the expedition, and the two groups decided to camp together. However, in the morning one of the Blackfeet stole a pair of rifles. There was a fight and two Blackfeet were killed. Lewis and his men fled, riding 120 miles in a day, afraid the Blackfeet would give chase.
