Kern National Wildlife Refuge is a 11,249-acre (45.52 km2) protected area located in the southern portion of California's San Joaquin Valley, 20 miles (32 km) west of the city of Delano. Situated on the southern margin of what was once the largest freshwater wetland complex known as Tulare Lake in the western United States, Kern National Wildlife Refuge provides an optimum wintering habitat for migratory birds with an emphasis on waterfowl and water birds. The wetlands provide habitat for birds as part of the Pacific Flyway.