John C. Boyle Reservoir was a 381-acre impoundment on the Klamath River that was removed in 2024 as part of a major dam removal project. The reservoir stretched 7.6 miles along the Klamath River, with Spencer Bridge crossing at its midpoint. The narrow reservoir had an average depth of 11 feet and maximum depth of 45 feet.

The Bureau of Land Management maintained Topsy Recreation Site, which provided a campground, boat launch, dock, and fishing pier. Prior to removal, the reservoir supported populations of largemouth bass (12-16 inches), black and white crappie, yellow perch, brown bullhead, and pumpkinseed sunfish. Water levels fluctuated up to 3 feet daily due to power generation operations.

The reservoir was created in the mid-1950s as part of the Klamath River Hydroelectric Project. Originally called Big Bend Reservoir, it was renamed in 1962 for John C. Boyle, an executive with California-Oregon Power Company. The dam's removal in 2024 was part of a larger project to restore salmon habitat and improve water quality in the Klamath River system.

The surrounding landscape features conifer forests with views of Aspen Butte and Mt McLoughlin. The area serves as a major stop on the Pacific Flyway, offering opportunities to spot bald eagles, osprey, and blue herons. The reservoir provided a water recreation destination in an otherwise dry region.

Note: As of 2024, this reservoir no longer exists following dam removal. The area is undergoing restoration to return the river to its natural state. All recreation facilities associated with J.C. Boyle Reservoir were closed by the Klamath River Renewal Corporation in 2023.