Clearwater River (Idaho)

Coordinates: 46°25′30″N 117°02′14″W / 46.42500°N 117.03722°W / 46.42500; -117.03722
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Clearwater River
ClearwaterRiver nearGreerID.jpg
Clearwater River near Greer Ferry
Map showing the Clearwater River watershed
Native nameKooskooskia (Nez Perce)
CountryUnited States
RegionIdaho County, Clearwater County, Shoshone County, Nez Perce County
CitiesOrofino, Lewiston
Physical characteristics
SourceMiddle Fork Clearwater River
 • locationConfluence of Selway River and Lochsa River, Idaho County
 • coordinates46°08′28″N 115°35′53″W / 46.14111°N 115.59806°W / 46.14111; -115.59806
 • elevation1,453 ft (443 m)
2nd sourceSouth Fork Clearwater River
 • locationNear Red River Hot Springs, Idaho County
 • coordinates45°52′09″N 115°18′32″W / 45.86917°N 115.30889°W / 45.86917; -115.30889
 • elevation4,285 ft (1,306 m)
Source confluenceKooskia
 • locationIdaho County
 • coordinates46°08′45″N 115°58′56″W / 46.14583°N 115.98222°W / 46.14583; -115.98222
 • elevation1,220 ft (370 m)
MouthSnake River
 • location
Lewiston, Nez Perce County
 • coordinates
46°25′30″N 117°02′14″W / 46.42500°N 117.03722°W / 46.42500; -117.03722
 • elevation
741 ft (226 m)
Length74.8 mi (120.4 km), Southeast-northwest[1]
Basin size9,645 sq mi (24,980 km2)
 • average15,300 cu ft/s (430 m3/s)
 • maximum109,000 cu ft/s (3,100 m3/s)[2]
Basin features
River systemSnake River
 • leftSouth Fork Clearwater River
 • rightMiddle Fork Clearwater River, North Fork Clearwater River, Potlatch River

The Clearwater River is in the northwestern United States, in north central Idaho. Its length is 74.8 miles (120.4 km),[1] it flows westward from the Bitterroot Mountains along the Idaho-Montana border, and joins the Snake River at Lewiston. In October 1805, the Lewis and Clark Expedition descended the Clearwater River in dugout canoes, putting in at "Canoe Camp," five miles (8 km) downstream from Orofino; they reached the Columbia Bar and the Pacific Ocean about six weeks later.

By average discharge, the Clearwater River is the largest tributary of the Snake River. The River got its name for the Niimiipuutímt naming as Koos-Koos-Kia - "clear water".[3]

The drainage basin of the Clearwater River is 9,645 square miles (24,980 km2). Its mean annual discharge is 15,300 cubic feet per second (430 m3/s)[4]


In the small town of Kooskia, the Middle Fork and South Fork of the Clearwater River join their waters to form the main stem of the Clearwater. The larger Middle Fork is made up of the combined flows of the Lochsa and Selway rivers which flow from the Bitterroot Mountains located to the east, while the much smaller South Fork originates in the Selway-Bitterroot Wilderness to the south. From the confluence, the Clearwater flows northwest, passing the Heart of the Monster site of the Nez Perce National Historical Park. U.S. Route 12 follows the river to Kamiah, where Lawyer Creek from the southwest joins it.

The river continues northwest through a canyon to the confluence with Lolo Creek from the east. It soon passes the town of Greer and receives Jim Ford Creek from the east. At Orofino, the river gains the waters of Orofino Creek and swings westward in a nearly straight line for about three miles (5 km), then receives the North Fork from the northeast at Ahsahka, close to Dworshak Reservoir. After the North Fork contributes its flow, the Clearwater continues west and receives Big Canyon Creek from the south and Bedrock Creek from the north.

As the river canyon cuts deeper into the Columbia Plateau, the Clearwater passes the unincorporated communities of Lenore and Myrtle, where it receives Cottonwood Creek from the southeast, and Arrow, where it receives the Potlatch River from the north. Lapwai Creek joins from the south, where the river passes close to Spalding. Here, U.S. Route 95 crosses the Clearwater and is co-signed with U.S. Route 12 along the river's north bank for several miles. The river soon widens and slows into the slack water of Lower Granite Lake as it approaches Lewiston. Just as it crosses the Idaho-Washington state line, it joins its waters with the Snake River.


The Clearwater breaks into several separate forks:

Clearwater River near Orofino, ID

River modifications[edit]

The Dworshak Reservoir is the only major lake on the Clearwater system, created from the Dworshak Dam, completed in the early 1970s. Dworshak Dam is on the North Fork of the Clearwater River and is just northwest of Orofino. There is no fish ladder; the dam blocks salmon and steelhead passage.


The border between Washington and Idaho was defined as the meridian running north from the confluence of the Clearwater River and the Snake River. Although this border is often referred to as the 117th meridian west longitude, the actual border line is slightly west (less than 2 miles) of the 117th meridian.[5]

See also[edit]


  1. ^ a b U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. "The National Map". Archived from the original on 2012-03-29., accessed May 3, 2011
  2. ^ "USGS Gage #13343000 on the Clearwater River near Lewiston". National Water Information System. United States Geological Survey. Retrieved 2010-03-09.
  3. ^ Rees, John E. (1918). Idaho Chronology, Nomenclature, Bibliography. W.B. Conkey Company. p. 64.
  4. ^ "Clearwater Subbasin Plan" (PDF). Archived from the original (PDF) on 2007-12-17. Retrieved 2008-09-13., Northwest Power and Conservation Council
  5. ^ "Washington State Constitution". Archived from the original on 2005-12-24. Article XXIV Boundaries

External links[edit]