The "Maryland Line" was a formation within the Continental Army, formed and authorized by the Second Continental Congress, meeting in the "Old Pennsylvania State House" (later known as "Independence Hall") in Philadelphia, Pennsylvania in June 1775.
Col. George Washington, delegate and formerly of the Virginia Regiment of the colonial militia, served as commander-in-chief of the colonial forces and he assumed command at Cambridge, Massachusetts outside of Boston, of the various units from several of the American colonies which surrounded Boston, laying siege to the British Army in June 1775. Washington's previous military experience had been during the late French and Indian War (1754–1763), (known in Europe as the Seven Years' War).
Not all Continental infantry regiments raised in a state were part of a state quota. On December 27, 1776, the Second Continental Congress gave commanding General George Washington temporary control over certain military decisions that the Congress ordinarily regarded as its own prerogative. These "dictatorial powers" included the authority to recruit and raise sixteen additional Continental infantry regiments at large.
Forman's, Gist's, Grayson's, and Hartley's Regiments were partially drawn from Maryland. Other Continental infantry regiments and smaller units, also unrelated to a state quota, were raised as needed for special or temporary service.
Under the assumption that paid soldiers furnished with rations and suits of clothes would be better soldiers, on 18 January 1776, the Maryland Provincial Convention established the Maryland Line as a regiment of uniformed regulars. According to Maryland State Archivist Ryan Polk, what distinguished the Maryland troops from other colonial levies was the time they spent drilling before joining the ranks of the Continental Army. This resulted in a disciplined, cohesive unit.
The term "Maryland Line" referred to the quota of numbered infantry regiments assigned to Maryland at various times by the Continental Congress. These, together with similar contingents from the other twelve colonies, formed the "Continental Line". The concept was particularly important in relation to the promotion of commissioned officers. Officers of the Continental Army below the rank of brigadier general were ordinarily ineligible for promotion except in the line of their own state.
The "Maryland Line" was assigned a quota of eight regiments in 1777, which was reduced to five in 1781. The regiments of the line were:
According to popular tradition, Washington expressed his high esteem for the Maryland Line after their heroic stand at the Battle of Long Island. Because of the long service of the high quality regiments, General Washington referred to the Maryland units as his "Old Line", giving the State of Maryland one of its nicknames as "The Old Line State".