The Mid-Columbia River Steelhead DPS includes all populations of steelhead in the Columbia River and its tributaries in Washington and Oregon, below natural and man made impassable barriers in streams above the Wind River, Washington, and the Hood River, Oregon (exclusive), upstream to and including, the Yakima River, Washington, excluding O. mykiss from the Snake River Basin. The Mid-Columbia Steelhead DPS was listed as threatened under the Endangered Species Act (ESA) in 1999.
The Mid-Columbia steelhead DPS contains four Major Population Groups (MPGs) - Yakima River, Cascades Eastern Slope Tributaries, John Day River, and Umatilla/Walla Walla Rivers. Collectively the four MPGs contain 17 extant (exiting) and 3 extirpated (locally extinct) independent populations. The Oregon portion of the DPS includes 10 extant populations – Fifteenmile Creek, Deschutes River Eastside, Deschutes River Westside, Upper Mainstem John Day, North Fork John Day, Middle Fork John Day, South Fork John Day, Upper Mainstem John Day, Umatilla River and Walla Walla River; and two (2) extirpated populations – Deschutes/Crooked River and Willow Creek. Five (5) extant populations and one (1) extirpated population of Mid-C steelhead reside on the Washington side of the Columbia River.
The State of Oregon monitors the Mid-Columbia steelhead populations that occupy Oregon tributaries in coordination with its co-managers, The Confederated Tribes of the Warm Springs Reservation of Oregon and The Confederated Tribes of the Umatilla Indian Reservation.