The Bear River Watershed spreads across 7,500 square miles of mountain and valley lands that encompass portions of Idaho, Utah, and Wyoming. Bear River is the main tributary to the Great Salt Lake and is the longest stream in the western hemisphere that does not empty into an ocean. Crossing state boundaries five times along its 500-mile path—the watershed is entirely enclosed by mountains, which form a huge basin with no drainage outlets.
The Bear River Basin is part of an overthrust belt where geologic forces have thrust layers of older rock on top of younger rock. Over millions of years, a depression in the earth's surface formed, completely closed by mountains, creating the Bear River watershed.
The Bear River and its tributaries supply water to thousands of acres of wetlands, providing critical habitat for a wide variety of wildlife—including more than 75 species of mammals, reptiles, and amphibians. Over 225 bird species have been identified in the basin area.
Since the early 1900s, the river has been harnessed for power generation and tapped for agricultural irrigation. More recently, recreation—such as hiking, camping, boating, fishing, and wildlife viewing—has become another important use of the basin's resources.
The Shoshone, Bannock, and Ute Indians once inhabited the Bear River Basin. Fur trappers from the Hudson's Bay Company began to arrive as early as 1812. Between 1840 and 1870, more than 500,000 emigrants traveled westward through this region. Logs cut high in the Uinta Mountains were milled into ties and floated down the Bear River for construction of the Union Pacific Railroad.