Baltimore County is a county located in the northern part of the U.S. state of Maryland. In 2004, its population was estimated to be 763,181.. Its county seat is Towson. The name of the county was derived from the barony of the Proprietor of the Maryland colony, C�cilius Calvert, 2nd Baron Baltimore, in County Longford, Ireland. It should be noted that Baltimore County does not actually include the city of Baltimore, which left the county to become an independent city in 1851.
The origin of Baltimore County is not known, the earliest known record of the county politically is January 12, 1659, when a writ was issued to its sheriff. Previously, Baltimore County was more known as a geographical entity than a political one, with its territorial limits consisting of the present day Baltimore City, Cecil and Harford Counties, as well as parts of Carroll, Anne Arundel, Frederick, Howard and Kent Counties.