in
Umatilla, July 2013 The Umatilla River's headwaters lie in the
Blue Mountains at the confluence of its north and south forks in the
Umatilla National Forest of northeastern Oregon. Flowing generally west, the river receives Lick Creek and Bear Creek, both from the
right before reaching the unincorporated community of
Bingham Springs. Further downstream it receives Rock Creek from the right, then Bobsled, Augur, and Ryan creeks from the left before entering the
Umatilla Indian Reservation and reaching the
unincorporated community of
Gibbon. From Gibbon to the river mouth, tracks of the
Union Pacific Railroad run parallel to the stream. Between Gibbon and
Cayuse, three creeks—Squaw, Buckaroo, and Coonskin—enter the river from the left. Downstream of Cayuse, Moonshine, Cottonwood, and Mission creeks also enter from the left. The river flows by
Mission at about
river mile (RM) 61 or river kilometer (RK) 98, leaves the Indian reservation, and reaches the city of
Pendleton at about RM 56 (RK 90), passing under
Oregon Route 11. Wildhorse Creek enters from the right, then Patawa Creek from the left. The river passes under
Interstate 84 (I-84) and receives McKay Creek from the left. Shortly thereafter,
Birch Creek enters from the left about from the
mouth. Coombs Creek enters from the left about below that, and then the river, turning north, flows along
Fort Henrietta Park in the city of
Echo and under I-84 again. The Umatilla reaches
Stanfield about from the mouth, then passes under
Oregon Route 207 and receives
Butter Creek from the left. Reaching
Hermiston at about RM 9 (RK 14), the river flows by a
United States Geological Survey (USGS)
stream gauge about from the mouth, then passes under
Interstate 82 and
Oregon Route 730 before entering the Columbia River at
Umatilla. The Umatilla River joins the Columbia at what is called
Lake Umatilla, a reservoir formed by the
John Day Dam on the Columbia. The confluence is from the Columbia's mouth on the
Pacific Ocean at
Astoria.
McNary Dam, another dam on the Columbia, is slightly upstream at about RM 292 (RK 470). ==Fish==