Butte Sink Wildlife Management Area is located in Colusa, Butte, and Sutter Counties. It is wetlands managed as part of the Sacramento National Wildlife Refuge Complex and is not open to the public. Within the 18,000-acre (73 km2) Wildlife Management Area, conservation easements have been purchased on 10,311 acres (41.73 km2), requiring landowners to maintain wetlands on their property in perpetuity. These lands are privately owned and closed to public access. In addition, a 733-acre (2.97 km2) area (owned in fee title) was established in 1980 to protect wetlands for wintering waterfowl. This area is known as the "Butte Sink Unit" (formerly known as the Butte Sink National Wildlife Refuge), and is also closed to public access.