Yakima River

Yakima River.
State Route 10 winds past the Yakima River near the town of Thorp.
Map of the Yakima River watershed
Location
CountryUnited States
StateWashington
CitiesCle Elum, Ellensburg, Yakima, Sunnyside, Richland
Physical characteristics
SourceKeechelus Lake
 • locationKittitas County, Washington
 • coordinates47°19′20″N 121°20′21″W / 47.32222°N 121.33917°W / 47.32222; -121.33917
 • elevation2,520 ft (770 m)
MouthColumbia River at Lake Wallula
 • location
Richland, Benton County, Washington
 • coordinates
46°15′10″N 119°13′51″W / 46.25278°N 119.23083°W / 46.25278; -119.23083
 • elevation
344 ft (105 m)
Length214 mi (344 km)
Basin size6,150 sq mi (15,900 km2)
Discharge 
 • locationKiona, RM 30
 • average3,493 cu ft/s (98.9 m3/s)
 • minimum225 cu ft/s (6.4 m3/s)
 • maximum59,400 cu ft/s (1,680 m3/s)
Discharge 
 • locationMabton, RM 60
 • average3,311 cu ft/s (93.8 m3/s)
Discharge 
 • locationUnion Gap, RM 107
 • average3,542 cu ft/s (100.3 m3/s)
Discharge 
 • locationUmtanum, RM 140
 • average2,430 cu ft/s (69 m3/s)
Basin features
Tributaries 
 • leftCle Elum River, Teanaway River
 • rightNaches River

The Yakima River is a tributary of the Columbia River in south central and eastern Washington state, named for the indigenous Yakama people. Lewis and Clark mention in their journals that the Chin-nâm pam (or the Lower Snake River Chamnapam Nation) called the river Tâpe têtt (also rendered Tapteete), possibly from the French tape-tête, meaning "head hit". The length of the river from headwaters to mouth is 214 miles (344 km), with an average drop of 9.85 feet per mile (1.866 m/km). It is the longest river entirely in Washington state.