Waldorf is an unincorporated community and census-designated place (CDP) in Charles County, Maryland, United States. Located 23 miles (37 km) south-southeast of Washington, D.C., Waldorf is part of the Southern Maryland region. It is an urban area, with a population (excluding the CDP of St. Charles) measured by the 2020 census at 81,410 within an area of 36.5 square miles. Waldorf has experienced dramatic growth, increasing its population 16 fold from fewer than 5,000 residents in 1980 to its current population. It is now the largest commercial and residential area in Southern Maryland as well as being a major suburb of Washington D.C.