Thornton is a census-designated place (CDP) in San Joaquin County, California, United States.

[3] Thornton is located along Interstate 5 7 miles (11 km) west-southwest of Galt.

[6] The community was named for Arthur Thornton, the original owner of the town site.

[5] According to the United States Census Bureau, the CDP covers an area of 2.2 square miles (5.6 km2), 98.70% of it land, and 1.30% of it water.

The racial makeup of Thornton was 554 (49.0%) White, 43 (3.8%) African American, 3 (0.3%) Native American, 45 (4.0%) Asian, 1 (0.1%) Pacific Islander, 443 (39.2%) from other races, and 42 (3.7%) from two or more races.