Bear, river, 350 mi (563 km) long, rising in the Uinta Mts., NE Utah, and flowing in a U-shaped course NW through Wyoming and Idaho, then S into Utah to enter Great Salt Lake. A perennial stream, the Bear played an important role in the development of the region by the Mormons in the mid-1800s. The Bear irrigates c.50,000 acres (20,230 hectares). At the river's mouth is Bear River National Wildlife Reserve.