Central Idaho is a geographical term for the region located northeast of Boise and southeast of Lewiston in the U.S. state of Idaho. It is dominated by federal lands administered by the United States Forest Service and the Bureau of Land Management. Idaho's tallest mountain, Borah Peak, is located in this region. A large part of the Sawtooth National Recreatio…Central Idaho is a geographical term for the region located northeast of Boise and southeast of Lewiston in the U.S. state of Idaho. It is dominated by federal lands administered by the United States Forest Service and the Bureau of Land Management. Idaho's tallest mountain, Borah Peak, is located in this region. A large part of the Sawtooth National Recreation Area is within Central Idaho.