| Lake Umatilla | |
| Location: | Oregon / Washington, United States |
| Coords: | 45.7175°N -120.6939°W |
| Basin Countries: | United States |
| Pushpin Map: | Oregon#Washington#USA |
| Pushpin Label Position: | bottom |
| Pushpin Map Alt: | Location of Lake Umatilla in Oregon and Washington, USA. |
Lake Umatilla is a 1100NaN0 long reservoir on the Columbia River in the United States, between the U.S. states of Washington and Oregon. It was created in 1971 with the construction of John Day Dam, and stretches upstream to the McNary Dam. It lies in parts of Sherman, Gilliam, Morrow, and Umatilla counties in Oregon, and Klickitat and Benton counties in Washington.