Wasco, CA. Sponsored Topics. Wasco (formerly, Dewey and Deweyville) is a city in the San Joaquin Valley, in Kern County, California, United States. Wasco is located 24 miles (39 km) northwest of Bakersfield, at an elevation of 328 feet (100 m). The population was 25,545 at the 2010 census, up from 21,263 at the 2000 census.