Elkridge is a census-designated place (CDP) in Howard County, Maryland, United States. The population was 22,042 at the 2000 census. Founded early in the 18th century, Elkridge is located at the confluence of three counties, the other two being Anne Arundel and Baltimore counties. It is bordered on the north by Catonsville, on the east by Linthicum and Baltimore-Washington International Airport, on the south by Dorsey, and on the west by Ellicott City and various small communities between it and Columbia.