As distinguished from the old Northwest Territory, is the region including the states of Oregon, Washington, and western Montana and Idaho. Characterized on the Pacific coast by a humid, forested area, and east of the Cascade Mountains by a high arid tableland and great fertile valleys, the region has varied industries, the most prominent being salmon fishing, lumbering, agriculture, and cattle raising. Its central waterway, the Columbia River, was discovered and claimed for the U.S. in 1792, and the Lewis and Clark expedition, as well as the fur-trading activities of John Jacob Astor, further established U.S. interests in the Northwest, later the cause of the Oregon Question, which was not finally settled until 1846. Up to this time, the history of the territory had been that of the fur trade and of pioneer immigration by way of the Oregon Trail, whose most famous figures were Jedediah Smith and Marcus Whitman. After 1850 began the marked development of agriculture and industry, with later homesteading encouraged by the railroading accomplishments of Henry Villard and James J. Hill. Washington Irving described the fur trade in Astoria; Honoré Morrow's novel We Must March tells the story of Marcus Whitman; Emerson Hough's 54–40 or Fight! and other books are concerned with the Oregon Question; Frank B. Linderman has written of frontier Montana; James Stevens and others have collected the Paul Bunyan stories of the Northwest lumber camps; Oregon in the early 1900s is described in H. L. Davis's Honey in the Horn; and modern life in the region is the subject of novels by Archie Binns and Robert Cantwell.