 st. charles is a planned community in charles county, maryland, united states. it is  south-southeast of washington, d.c.,  from northern virginia and immediately south of waldorf, which is the mailing address. (st. charles comprises nearly all the population of waldorf's zip code 20602, and much of 20603). at the 2000 census, it was delineated as a census-designated place (cdp), with a population of 33,379. it was included in the waldorf cdp for the 2010 census. ==history== planning for st. charles was started in 1965 by st. charles city, inc.{{cite web |url=http://plato.mdarchives.state.md.us/msa/stagser/s1500/s1529/cfm/dsp_unitlist.cfm?county=ch&qualifier=s&series=1242&vref=10&vlabel=plat%20book&vtype=b |title=plat book 10, pp. 10-13, st. charles, section 1 |date=1965-09-30 
1965_establishments_in_Maryland Former_census-designated_places_in_Maryland Planned_cities_in_the_United_States Populated_places_established_in_1965 Washington_metropolitan_area