The Fish Slough Area of Critical Environmental Concern is a protected slough in Inyo County, eastern California. It is located on the western side of the Chalfant Valley, 5 miles (8.0 km) north of Bishop in the northern Owens Valley area. Its 36,000 acres (15,000 ha) were designated as an Area of Critical Environmental Concern (ACEC) in 1982, and is managed by the Bureau of Land Management. The Fish Slough Area is an oasis in the middle of the otherwise arid volcanic tableland. In 1975, Fish Slough was designated as a National Natural Landmark by the National Park Service.