The valley of the Snake River, a historic passage from the Midwest to the Northwest, has been a primary route for travel since the days of Indians and fur traders. The Oregon Trail forded the river at Old Fort Boise, the Hudson's Bay Company post twelve miles upstream. Many famous early westerners saw this valley, though the look of the land changed after white settlement brought irrigated farms. Today the river provides both irrigation and power along its thousand-mile course from the Yellowstone to the Columbia. Highways, railroads, and airlines follow its open valley east of here, but to the north Hell's Canyon of the Snake remains almost impassable to man.