Bitter Creek National Wildlife Refuge, Nature reserve in Ventura County, United States.

Bitter Creek National Wildlife Refuge is a nature reserve in the eastern foothills of the Coast Ranges in Ventura County, California. The land is made up of dry grasslands, oak woodland, and chaparral across hilly terrain.

The refuge was established in 1985 to preserve foraging and roosting habitat for the California condor, on land that had been a cattle ranch. The last wild female condor was trapped here in 1986, and the last wild condor in 1987, as the remaining birds were taken into a captive-breeding program.

The refuge lies in the foothills of the southwestern San Joaquin Valley in Kern County, and the land was a cattle ranch before the refuge was created in 1985. Guided interpretive tours are the only way in, and they are built around watching condors feed and roost. The San Andreas Fault Rift Zone cuts the refuge from northwest to southeast and forms Bitter Creek Canyon.

Public access to the refuge is limited, and visitors are advised to check current conditions before heading out, as roads in the area can be rough. Condor viewing is possible from pullouts along Cerro Noroeste Road and Highway 166, and mornings tend to offer better chances of spotting the birds.

The last wild female California condor was trapped here in 1986, part of the effort to save the species. The refuge lies within the South Coast Missing Linkages plan, connecting the Tehachapi, Santa Monica–Sierra Madre and Sierra Madre–Castaic wildlife corridors.