The Willamette River flows entirely within the state of Oregon. It is one of the few American rivers of any size that flow north. From a mountainous region at the head of a valley the Willamette emerges as three forks. The Coast Fork begins as a small mountain stream and joins the Middle Fork that flows from the base of Emigrant Butte. These two forks are then joined by the third fork, the McKenzie. The Willamette was not explored by a single adventurer. In 1792 the English navigator Lieutenant William R. Broughton, a member of the British maritime expedition of Captain Vancouver, sailed up the Columbia and briefly entered the mouth of the Willamette. About 13 years later, William Clark of the Lewis and Clark Expedition advanced a few miles up the river before turning back. In his journal he noted a river he called "the Multnomah," after the tribal nation that resided in the area. It was not until the surge of traders and trappers that the river was explored farther, and it was at that time that the Multnomah became known as the Willamette. The name's current spelling was the result of an 1841 visit by Lieutenant Charles Wilkes of the U.S. Exploring Expedition. In the early 1830s, retiring Hudson's Bay Company employees began to settle on the prairies along the Willamette River, where they had previously trapped. Those early settlers were soon followed by missionaries and then early pioneers. It was with the first settlements that the mills, warehouses and ferry landings were built. The river not only provided a means of transportation, but also a way to transport crops to market. As early as 1846, Robert "Doc" Newell, ex-trapper, operated three flatboats between the Willamette Falls and Champoeg, the center of trade on the middle river. By 1849, the gold discovery in California caused a mass explosion of fortune seekers. Those that stayed, hurried to increase agriculture production to supply the miners' needs. Sawmills and flour mills ran at maximum speed. The landings and ferries operated at full capacity. Today the Willamette River is used extensively for recreation.