Baltimore, the 12th largest city in the United States, is named "Charm City" for its residents well-established concern for the quality of life.Baltimore was named for Cecilius (Cecil) Calvert, the second Lord Baltimore and the proprietor of Maryland, who in turn took his title from his barony estates in Longford County, Ireland.

While archeological evidence shows that the area has supported human inhabitation for 9000 years, by the 1650's when European settlement began, Baltimore County was primarily a geographical entity more than a political one. Its territorial limits consisted of Baltimore City, Cecil and Harford Counties, as well as parts of Carroll, Anne Arundel, Frederick, Howard and Kent Counties. The legal origin of Baltimore County is not known, but it was in existence by January 12, 1659, when a writ was issued to the county sheriff. Formal county boundaries were mentioned when Cecil County was formed out of Baltimore County in 1674.

Old Baltimore County, was the sixth county to be established by the colonial assembly in 1659, and was the first in the northern part of Maryland. The original area of Baltimore County was much larger then its present size. Its first county seats were Old Baltimore on the Bush River and Joppa on the Gunpowder River, both of which are in Harford County today.

In 1854, Towsontown, now known as Towson, became the current county seat. The cornerstone of the courthouse was laid on October 19, 1854.