Ascending the Missouri River

Most of the expedition (between 45 and 50 members) started out on a rainy May 14, 1804, crossing the Mississippi to begin the ascent of the Missouri River. Lewis joined the party in St. Charles, Missouri, where the party remained until May 21. The expedition moved slowly against the current, passing present-day Kansas City, Missouri, in late June and Omaha, Nebraska, by late July under the sweltering summer heat. They traveled westward parallel to the Nebraska-South Dakota border for 10 days in late August through early September, and then turned north into central South Dakota, constantly buffeted by prairie winds. Their first frost blanketed them on October 5 as they neared the South Dakota-North Dakota state line. By mid-October they experienced their first snows near present-day Bismarck, North Dakota, and established winter quarters at Camp Mandan on November 2. Here they would endure the rigors of prairie winter, including the coldest temperature of the year.