Lewis River (Washington)

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Lewis River
Lower Falls Lewis River.jpg
Lower Falls of the Lewis River
Name origin: A. Lee Lewis, early settler
Country United States
State Washington
County Skamania, Clark, and Cowlitz
Source Mount Adams
 - location Cascade Range, Skamania County, Washington
 - elevation 7,194 ft (2,193 m) [1]
 - coordinates 46°13′28″N 121°31′44″W / 46.22444°N 121.52889°W / 46.22444; -121.52889 [2]
Mouth Columbia River
 - location opposite St. Helens, Oregon, and on the border between
Cowlitz and Clark counties
, Washington
 - elevation 10 ft (3 m) [2]
 - coordinates 45°51′04″N 122°46′49″W / 45.85111°N 122.78028°W / 45.85111; -122.78028Coordinates: 45°51′04″N 122°46′49″W / 45.85111°N 122.78028°W / 45.85111; -122.78028 [2]
Length 95 mi (153 km) [3]
Basin 1,046 sq mi (2,709 km2) [4]
Discharge for mouth (average); max and min at Ariel, WA
 - average 6,125 cu ft/s (173 m3/s) [5]
 - max 129,000 cu ft/s (3,653 m3/s)
 - min 807.2 cu ft/s (23 m3/s)
Location of the mouth of the Lewis River in Washington

The Lewis River is a tributary of the Columbia River, about 95 miles (153 km) long, in southwestern Washington in the United States. It drains part of the Cascade Range north of the Columbia River. The drainage basin of the Lewis River covers about 1,046 square miles (2,709 km2).[4] The river's mean annual discharge is about 6,125 cubic feet per second (173.4 m3/s).[5] Unlike nearby Lewis County and Fort Lewis the Lewis River was not named for Meriwether Lewis, but rather for A. Lee Lewis, an early settler who homesteaded near the mouth of the river.[6]


Upper Falls
Kayaker in the gorge of East Fork Lewis River (Dragon's Back)

The Lewis River rises in the Cascades in northeastern Skamania County, high on the west flank of Mount Adams, approximately 75 miles (121 km) northeast of Portland, Oregon. It flows generally southwest through Gifford Pinchot National Forest, across central Skamania County, passing south of Mount St. Helens. It forms the boundary, along the Dark Divide on its north side, between Cowlitz County, to the north, and Clark County, to the south. Towns along the river include Cougar, Ariel, and Woodland. In its lower 10 miles (16 km), it turns sharply south, then west, and enters the Columbia from the east, opposite St. Helens, Oregon, approximately 15 miles (24 km) north of Vancouver, Washington. The mouth of the Lewis River is at Columbia river mile (RM) 87 or river kilometer (RK) 140.[5]

Near the confluence with the Columbia River, the Lewis River is joined by the East Fork Lewis River. The main Lewis River, sometimes called the North Fork Lewis River,[2] forms the boundary between Clark and Cowlitz counties, while the East Fork divides Clark County in half. The East Fork flows westward from headwaters on the western flanks of Lookout Mountain in Skamania County. Parks along the East Fork include Moulton Falls, Lucia Falls, Lewisville, and Paradise Point. A variant name of the East Fork is the South Fork Lewis River.[7]

River modifications[edit]

It is impounded for hydroelectricity in its middle course by Swift Dam, forming Swift Reservoir; Yale Dam, forming Yale Lake; and Merwin Dam, forming Lake Merwin.

See also[edit]


  1. ^ Source elevation derived from Google Earth search using GNIS source coordinates.
  2. ^ a b c d "Lewis River". Geographic Names Information System (GNIS). United States Geological Survey (USGS). October 10, 1979. Retrieved October 13, 2008.
  3. ^ "Online Topographic Maps from the United States Geological Survey". TopoQuest. Retrieved October 14, 2008.
  4. ^ a b "Description: Lewis River Drainage, Mount St. Helens, Washington". United States Geological Survey. 1999. Retrieved October 14, 2008.
  5. ^ a b c Lower Columbia Fish Recovery Board (December 2004). "Volume II – Subbasin Plan Chapter G – NF and EF Lewis" (pdf). Lower Columbia Salmon Recovery and Fish & Wildlife Subbasin Plan. Northwest Power and Conservation Council. Retrieved October 14, 2008.
  6. ^ Phillips, James W. (1971). Washington State Place Names. University of Washington Press. ISBN 0-295-95158-3.
  7. ^ "East Fork Lewis River". Geographic Names Information System (GNIS). United States Geological Survey (USGS). September 10, 1979. Retrieved October 13, 2008.

External links[edit]