The origin of the name Rosedale is not documented with certainty. However, a 1950 fourth grade class was told to interview family and friends about the history of the Rosedale community. From that activity came an explanation. Rosedale is an unincorporated community and a census-designated place in Baltimore County, Maryland, United States. The population was 19,199 at the 2000 census. Rosedale, a community northeast of the city of Baltimore, was a farming community from the time of the first settlers until suburban development began after World War II. State Route 7, which runs through the community, carried George Washington to New York in 1789 where he was inaugurated as the 1st American president.