Umatilla National Wildlife Refuge, was established in 1969 for wildlife habitat lost to flooding caused by the construction of the John Day Lock and Dam.

The 25,347 acre refuge, located in the arid Columbia Basin of northeast Oregon and southeast Washington astride the Columbia River, includes open water, shallow marshes, backwater sloughs, croplands, islands, and shrub-steppe uplands.

Migrating waterfowl, bald eagle, colonial nesting birds, migratory songbirds, resident wildlife and rare and endangered species can be found on the refuge. It is strategically located within the Pacific Flyway to provide Arctic nesting geese and ducks a wintering site and a resting stopover.

Established in 1969 as mitigation for habitat lost through flooding caused by the construction of the John Day Dam on the Columbia River, Umatilla Refuge is a mecca for birdwatchers and wildlife enthusiasts. Its more than 22,800 acres are a varied mix of open water, slough, shallow marsh, riparian woodlands, seasonal wetlands, cropland, islands, and shrub-steppe upland habitats. The scarcity of wetlands and other natural habitats in this area make the refuge vital to migrating waterfowl, bald eagles, colonial nesting birds, and other migratory and resident wildlife. The refuge is divided into six units: two in Oregon, three in Washington, and one 20-mile stretch of the Columbia River.

The building of dams on the Columbia River began in the 1930s and changed it from a narrow fast-flowing river to a wide slow-moving reservoir. In some places, the river's depth was raised 25 feet. Many islands, riparian areas, and other habitats were flooded, but other arid lands were transformed into wetlands. Native cottonwoods, willows, cattails, and bulrush began to appear in previously deserted desert environments. McCormack Slough in Oregon and Paterson Slough in Washington are good examples of wetlands created by rising Columbia River water levels.

At higher elevations, above the Columbia's reach, the refuge's plant communities are dominated by species capable of tolerating the hot, dry conditions of the Columbia Plateau. Common shrubs include sagebrush, bitterbrush, and rabbitbrush. Native bunchgrasses such as basin wild rye, Indian ricegrass, Idaho fescue, and Sandberg bluegrass were once common here, but today they must compete with very successful exotic plants such as cheatgrass, knapweed, tumbleweed, and perennial pepperweed.

Islands in the Columbia River are an important sanctuary for birds year round. Ducks, Canada geese, great blue herons, and black-crowned night herons nest here in spring and summer. Thousands of ducks and geese winter on the islands, and many different species rest here during spring and fall migration.