War Office 12, generated by the Commissary General of Musters Office, comprises the Household troops, the cavalry, Guards and regular infantry regiments of the line; as well as, special regiments or corps, colonial troops and various foreign legions and troops.
The muster rolls record the name, rank, military station and pay period of each soldier while they were with the regiment. They were prepared by the commanding officer of each company of a regiment for the purpose of paying the officers and soldiers. During a muster, each man was physically checked against his name on the roll and a note was made if their circumstances had changed since the last muster, for example, on duty, recruiting, sick, furlough, deserted, transferred or died. In addition, notes related to officers include promoted, absent, and resigned. Pay lists record rate of pay.
The 38th served under various colonels' names until designated the 38th Regiment of Foot in 1751. When troubles threatened with the Colonies, the 38th was one of the first corps despatched from Ireland to America. Landing in Boston in July 1774, the 38th found themselves involved in the first military engagement of the American war: Concord and Lexington, April 1775. The battle on Bunker's Hill took place on June 17th, 1775 and was one of the crowning victories for the 38th and the whole of the British army. With the American colonists' Declaration of Independence, General Howe affected the landing of his troops on Long Island which included the 38th and attacked Washington's army successfully before Brooklyn Heights. The 38th was stationed at Fort Washington and Long Island during the war and was involved in the following conflicts:
- 1776 New York Campaign
- 1776, August, Battle of Long Island, also known as the Battle of Brooklyn, successful
- 1776, November, Battle of Fort Washington, commanded by Lord Percy, successful
- 1776, September, Battle of Harlem Heights, capture of Fort Lee, flank companies of 38th participate
- 1777 New Jersey Campaign, as part of the Brunswick, New Jersey garrison
- 1777, Philadelphia Campaign
- 1777, September, Battle of Brandywine located west of Philadelphia, successful
- 1777, October, after the capture of Philadelphia by the British, the Battle of Germantown, located north of Philadelphia, successful
- 1778 France declared war on Britain
- 1778, June, Battle of Monmouth in New Jersey, under the new commander, General Clinton, who had been given orders to retreat from Philadelphia to New York, flank companies of 38th participate
- 1778, July, defence of Newport, Rhode Island
- 1778, August, under General Pigot, the Battle of Rhode Island, also known as, the Battle of Quaker Hill, in which the Americans tried unsuccessfully to recapture the Island from the British, now known as Aquidneck Island
- 1778, After September, regiment returned to New York
- 1779 Clinton moved the main British effort to the South
- 1780, June, Battle of Springfield, New Jersey, the last major engagement in the north, British under von Knyphausen attack George Washington's army, unsuccessful
- 1781, September, participated in the raid on New London, Connecticut, commanded by Benedict Arnold who had switched sides, this expedition was to be its last of the war
- 1783, after a brief stay in Halifax, returned home to England.
These muster rolls for the 38th Regiment of Foot are organised chronologically and contain the following pay periods: Reel 1 - 7 May 1774 to 24 December 1778; Reel 2 - 25 December 1778 to 24 December 1788. The remarks indicate that Captain Charles Lumm was Aid de Camp to General Pigot, Captain Henry Fox was Aid de Camp to General Howe, and Captain William Crosbie was Aid de Camp to General Clinton. It is also noted in the muster roll signed 21 December 1779 that General Pigot was "on leave in Europe" and this remained the case for the rest of the musters. Lt. Colonel Henry Fox was noted as commanding the Second Battalion of Grenadiers in the musters for the last half of 1780 through the first half of 1782; as well, William Handfield was indicated as Deputy Quarter Master General at Halifax in the muster covering 25 Dec. 1782 to 24 June 1783.
The senior officers named on the musters are: Lieutenant General Lord Blayney, Lieutenant Colonel, later Lieutenant General Sir Robert Pigot; Lieutenant Colonels William Butler (1775-78), Henry Fox (1778-?) and William Handfield; Majors Andrew Bruce, Daniel Disney, Lord Cathcart, and Eyre Power French. Captains on the muster roll for 7 May 1774 to 24 December 1774 include: John Otto Bayer, St. Laurence Boyd, William Crosbie, Henry Fox, Charles Lumm, Hugh Magenis, and Charles Norman. With Bayer's retirement, William Wade is promoted in 1776, and in 1777 Matthew Millett is promoted. Other company captains appearing thereafter during the American War include: Thomas Russell, Nathaniel Phillips, Henry Pottinger, George Cleghorn, William Braban, and John Sargent.
For the period of the American war, the places attached to the signatures on each muster included the following: Boston, Charlestown, Staten Island, Brunswick, Camp New York, Philadelphia, Rhode Island, Flushing Fly Long Island, Jamaica Long Island, Bedford Long Island, East Chester, Camp Valentine Hill, Harlem Heights, and Fort Knyphausen.
While in New York in 1782, the regiment received its county title of the 1st Staffordshire.