Smartsville is a census-designated place in Yuba County, California, United States, in the foothills of the Sierra Nevada. It is one of the many historic towns in California's gold country, and is today a California Historical Landmark. Located at an altitude of 669 feet, Smartsville lies about 15 miles east-northeast of Marysville, along State Route 20. The population was 177 at the 2010 census.