History of the Expedition Under the Command of Captains Lewis and Clark, Vol. 2. / To the Sources of the Missouri, Thence Across the Rocky Mountains and Down the River Columbia to the Pacific Ocean. Performed During the Years 1804-5-6.

The narrative follows an overland expedition traveling by canoe down the Columbia to the Pacific, confronting dangerous rapids, tides, and relentless rains that force the party to establish winter quarters. Detailed ethnographic observations describe numerous coastal and riverine Indigenous peoples—their houses, dress, burial customs, methods of catching and drying vast salmon runs, trade practices centered on blue beads, and social habits such as gambling. Natural-history entries catalog local plants and animals, while episodic adventures include whale-oil retrieval, salt-making, and hazardous portages. After securing friendly relations and leaving a written notice of their crossing, the party prepares to retrace its route across the mountains.