The population in 2008 is approximately 300. This is an approximation as the community borders are undefined and opinions on what outlying areas are actually part of Clarksburg vary from one source to the next. The portion of Sacramento County directly across the Sacramento River was once considered part of the community due to the ferry crossing that existed at Clarksburg from 1920 until the Freeport Bridge opened on New Year's Day in 1930. The ferry itself sank in November, 1928. Some of the older members of the community still refer to that adjoining area of Sacramento County as Clarksburg for that reason.