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Northwest: Idaho, Oregon, Washington

rise almost a mile and a half above the surface of the Snake River at the canyon’s floor. In parts of northwest Idaho, the mountains give way to rolling hills or prairie land. But in southern Idaho, the Snake River Plain forms a dramat- ic break in the Rockies. This crescent- shaped depression sweeps east to west across the state for a distance of some 350 miles (563 km). Its width varies from about 30 miles to about 75 miles (48 km to 121 km). The Snake River Plain is home to most of Idaho’s good farmland as well as to many of its towns and cities. Overall, it’s fairly level. However, its geology is complex, and the region contains many unusual and dramatic features. These include lava fields, hot springs, buttes , the majestic Shoshone Falls, and even high desert sand dunes. Mountains and valleys cover south- eastern Idaho, south of the Snake River Plain. The southwestern part of the state consists largely of low moun- tains and plateaus . Idaho has an abundance of rivers and creeks. The Snake River, which

Did You Know?

runs more than 1,000 miles (1,600 km), is the most important. Originating in northwestern Wyoming, the Snake crosses into Idaho at the Palisades Reservoir in Bonneville County. The river arcs west across the Snake River Plain, enters Oregon, and then loops back, flowing northward along the Idaho-Oregon border for about 215 miles (346 km). It follows Idaho’s border with Washington for another 30 miles (48 km) or so before turning west again. The Snake empties into the Columbia River in Washington. Over its entire course, the Snake drops a total of 9,500 feet (2,895 m) in elevation. This A wildfire believed to be the largest in U.S. history ravaged the Idaho Panhandle, along with western Montana, on August 20 and 21, 1910. The Big Blowup, as the inferno came to be called, consumed about 3 million acres of forested land and claimed at least 85 lives.