Decision at the Marias

Decision at the Marias. Lewis in Blackfoot Country. On the evening of June 2, 1805 the Corps of Discovery arrived at the mouth of an unknown river flowing from the north. The river had not been mentioned by the Hidatsa nor was it noted on their maps. The two rivers were equal is size. Which was the true Missouri? , The Captains decided to explore both forks. On June 4 Lewis went up the north branch and Clark journeyed to the south. After several days of exploration, the Captains decided that the south fork was the true Missouri; the north fork was named for Maria Wood, Lewis's cousin. , Their decision was made despite objections to the contrary from the rest of the Corps, but they agreed to "follow them anywhere." A wrong decision may have doomed the expedition. A few days later Captain Lewis found the Great Falls and the Captains were vindicated. , The region was in the heart of Blackfoot Country, and the favored location for winter camps of the Piikani. Fort Piegan was established in 1831 and it became an important fur trade region.