The John Day Dam is a concrete gravity run-of-the-river dam spanning the Columbia River in the northwestern United States. The dam features a navigation lock plus fish ladders on both sides. The John Day Lock has the highest lift of any U.S. lock. The reservoir impounded by the dam is Lake Umatilla, and it runs 76.4 miles (123.0 km) up the river channel to the foot of the McNary Dam. John Day Dam is part of the Columbia River Basin system of dams.