The Sacramento National Wildlife Refuge Complex includes five National Wildlife Refuges (NWR) and three Wildlife Management Areas (WMA)

• Sacramento NWR

• Delevan NWR

• Colusa NWR

• Sutter NWR

• Sacramento River NWR

• Llano Seco Unit of the Steve Thompson North Central Valley WMA

• Butte Sink Unit of the Butte Sink WMA

• Willow Creek-Lurline WMA

The Complex's National Wildlife Refuges were established between 1937 and 1989.  Four of these refuges (Sacramento, Delevan, Colusa and Sutter) were established primarily to provide wintering habitat for waterfowl and in some cases to reduce crop damage by waterfowl.  The Sacramento River NWR was established to help protect and restore riparian habitat along the Sacramento River between Red Bluff and Colusa.  All NWR lands are owned and managed by the U.S. Fish & Wildlife Service.

The Complex's Wildlife Management Areas were established between 1979 and 1991 in order to preserve wetland habitat for wintering waterfowl and other wetland-dependent wildlife.  The WMAs consist of a combination of private lands protected with conservation easements and Service-owned lands (the Butte Sink Unit of the Butte Sink WMA, and the Llano Seco Unit of the Steve Thompson North Central Valley WMA). The conservation easements are owned and managed by private landowners, and the Service-owned lands are owned and managed by the U.S. Fish & Wildlife Service.