Department of
Environmental Quality

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DEQ's Lewiston Region in north Idaho includes Clearwater, Idaho, Latah, Lewis, and Nez Perce Counties. The region is home to about 7.8% of the state's population, as well as both the University of Idaho and Lewis-Clark State College. The region covers 16.5% of the state's geographical area and contains more designated wilderness than any other DEQ region.  Lewiston, the largest city in the region, boasts Idaho's only seaport (on the Clearwater River) and has the lowest elevation of any town in Idaho (738 feet). Other major cities include Moscow, Grangeville, and Orofino. The Lewiston Region shares its borders with Oregon, Washington, Montana, and the Nez Perce Tribe, prompting coordination of shared resources. Timber product industries and recreation are important to the economic base of the region.

The Lewiston Region is known for the timbered watersheds of the Clearwater, Selway, Palouse, and Lochsa Rivers; the Snake River Canyon and Salmon River Basins; and the rolling hills of the Palouse and Camas Prairies.  Perhaps the most notable natural feature of the Lewiston Region is the varied topography: both mountains and canyons dominate the landscape. The most notable of these canyons is Hells Canyon, the deepest gorge in North America. The best known is likely the Salmon River Canyon, which attracts whitewater rafters from around the world.

Clearwater Basin Advisory Group

The Clearwater Basin Advisory Group consists of 10 members appointed by the director to represent stakeholder groups from northern Idaho. The BAG meets periodically to advise DEQ on surface water issues throughout the region. Learn more.

Water Quality Plans & Reports

Subbasin assessments and surface water quality improvement plans have been developed for a number of water bodies in DEQ's Lewiston Region. In addition, numerous studies have been conducted of ground water resources in the area. Access the plans and reports here.