Princeton is a census-designated place in Colusa County, California. It lies at an elevation of 82 feet. Its ZIP code is 95970 and its area code is 5…Princeton is a census-designated place in Colusa County, California. It lies at an elevation of 82 feet. Its ZIP code is 95970 and its area code is 530. Princeton's population was 303 at the 2010 census.