Klamath is an unincorporated, rural, census-designated place (CDP) in Del Norte County, California, situated on US Route 101 inland from the mouth of the Klamath River. The population was 779 at the 2010 census, up from 651 at the 2000 census. Klamath is at an elevation of 30 feet (9 m).
According to the United States Census Bureau, the CDP has a total area of 12.5 square miles (32.5 km²), all of it land.
The 2010 United States Census reported that Klamath had a population of 779. The population density was 62.1 people per square mile (24.0/km²). The racial makeup of Klamath was 379 (48.7%) White, 1 (0.1%) African American, 325 (41.7%) Native American, 3 (0.4%) Asian, 0 (0.0%) Pacific Islander, 5 (0.6%) from other races, and 66 (8.5%) from two or more races. Hispanic or Latino of any race were 90 persons (11.6%).