Owyhee Reservoir or Owyhee Lake is a reservoir on the Owyhee River in Malheur County, Oregon, United States. Located in far Eastern Oregon near the Idaho border, the reservoir is Oregon's longest at 52 miles (84 km). The 13,900-acre (56 km²) lake is home to several species of fish, including crappie, rainbow trout, largemouth bass, smallmouth bass, yellow perch, and brown bullhead. An artificial lake, it was created in 1932 with the completion of the Owyhee Dam.