Missouri marked both the beginning and the end of the Lewis and Clark Expedition. After the United States took ownership of the Louisiana Territory in St. Louis in March 1804, Meriwether Lewis, William Clark, and their Corps of Discovery left winter camp at Wood River, made a final recruiting stop in St. Charles in May, and began their journey up the Missouri River toward the Pacific. With 45 members at the outset, including army sergeants and privates, Clark's slave York, a French-Shawnee interpreter, and French-Canadian, French-Omaha, and French-Missouri Indian boatmen, the expedition spent 66 days crossing what is now Missouri on the westward journey and returned through the state in 1806, covering the same 600 miles in just two weeks. The Missouri River dominated the early expedition, as the 55-foot keelboat and two smaller pirogues struggled against swift current, snags, sandbars, driftwood, collapsing banks, heat, and mosquitoes, often forcing the crew to tow the boat from shore and repair broken equipment. Journal accounts recorded both hardship and resolve, including the saving of the keelboat above the Grand River on June 14 by extraordinary exertion. In Missouri the expedition also encountered traders, signs of Indian war parties, and Indian pictographs, while the journals vividly described forests, bluffs, prairies, caves, creeks, springs, and the transition from timbered eastern Missouri to western prairie. The return to St. Louis ended hopes for a Northwest Passage, but the expedition had reached the Pacific, met nearly 50 Indian nations, compiled detailed records of 300 previously undescribed animals and plants, ascended the full length of the Missouri River from its mouth to its source, explored much of the Columbia River, and helped establish a U.S. claim to the Pacific coast.