Saint Charles
- Country: United States
- State: Maryland
- Population: 33,379 (2000)
- Latitude: 38° 36.2' N (38.603°)
- Longitude: 76° 56.3' W (-76.939°)
- Elevation: 70 m/230 ft. above sea level
- Time zone: America/New_York (UTC -05:00); DST observed (UTC -04:00)
- Alternate names: St. Charles