The Maryland National Guard traces its roots through the long-time previous colonial and state militia to March 1634, with the landing of two English militia captains from the two settlement expeditionary ships, The Ark and Dove off the north shore of the Potomac River near the confluence with Chesapeake Bay at the first provincial capital, St. Mary's City in later St. Mary's County.

During the American Revolution, members of the "Maryland Line" repeatedly charged a vastly superior British force at the Battle of Long Island, buying time for the Continental Army to escape.

During the War of 1812, the Maryland militia held the line at the Battle of North Point in 1814, commanded by Brigadier General John Stricker.

[2] The 175th Infantry (ARNG MD), derived from the 5th Regiment, is one of only nineteen Army National Guard units with campaign credit for the War of 1812.

Steuart moved south for the duration of the American Civil War, and much of the general's property was confiscated by the Federal Government as a consequence.

During the Great Railroad Strike of 1877, on July 20 Governor Carroll called up the 5th and 6th Regiments from Baltimore to stop strikers in Cumberland from disrupting rail service.

In response to Pancho Villa's cross-border raids, the Maryland National Guard was called up in 1916 and deployed for seven months to the town of Eagle Pass, Texas, on the Mexican border.

[14] During the First World War, most Maryland National Guard troops served as part of the 29th Division, and their campaign credits include Meuse-Argonne.

In addition, the 1st Separate Company, an all-black unit, served as part of the 372nd Infantry Regiment, although ostensibly assigned to the 93rd Division, actually fought under French control.

The 231st Transportation Truck Battalion was the first National Guard unit to land in Korea, and were immediately put to use keeping supplies flowing within the Pusan Perimeter.

[15] 200th and 290th Military Police Companies and 1229th transportation co November 1990 - April 1991 - deployed to Saudi Arabi near the Iraq border in support of Operations Desert Shield/Storm.

Since the September 11 attacks, the Maryland Army National Guard has mobilized a number of units, including the 58th Infantry Brigade Combat Team, for service in Iraq; Afghanistan; Guantanamo Bay, Cuba; and Kosovo.

Guardsmen from the 115th Military Police Battalion were among the first and most heavily called upon, having arrived at the Pentagon on September 12 and subsequently served in Iraq, Afghanistan, and Guantanamo Bay.