Waldorf is an unincorporated community and census-designated place in Charles County, Maryland, United States. It is  south-southeast of Washington, D.C. The population of the census-designated area (now including the large planned community of St. Charles) was 67,752 at the 2010 census. Waldorf was settled before 1900 as a rural crossroads with a train station and was called "Beantown" after a local family.