McKay Reservoir is a reservoir in Umatilla County of the U.S. state of Oregon. It is an impoundment of McKay Creek, a tributary of the Umatilla River. The reservoir is located 6 miles (9.7 km) south of Pendleton on U.S. Route 395. The reservoir has a capacity of 65,534 acre feet (80,835,000 m³) of water. The reservoir and land that immediately surrounds it are designated as the McKay Creek National Wildlife Refuge. The reservoir and creek that it impounds are named for Dr. William C. McKay. McKay was an early settler in the Pendleton, Oregon area.