This Regiment traced its lineage to Thomas' Massachusetts Regiment, one of 27 infantry regiments raised by the Bay Colony in the spring of 1775 after the outbreak of the American Revolution. Incorporated into the Continental Army on June 14, 1775, the Regiment fought in the Siege of Boston as part of General George Washington's Main Army. When Washington reorganized the Continental Army for 1776, he consolidated the John Bailey and Theophilus Cotton Regiments, designating the new entity as the 23rd Continental Regiment. The 23rd endured defeat in Washington's unsuccessful defense of New York City, then tasted victory at Trenton and Princeton. After a September 16th Congressional reorganization, Washington combined the 23rd and 7th Regiments with elements of the 13th and 21st, assigning what was then known as Bailey's Regiment to the Northern Department, under the command of Brigadier General Ebenezer Learned, to defend upstate New York against the pending British invasion. The Regiment fought at Saratoga after the evacuation of Fort Ticonderoga, then marched under General Benedict Arnold to the relief of Fort Stanwix. The Regiment also fought in the Philadelphia Campaign, at Freeman's Farm, and Bemis Heights. The Regiment returned to the Main Army on Oct. 27, 1777, and after fighting in the Monmouth Campaign it was reassigned to the Highlands Department in 1778. Re-designated as the 2nd Massachusetts Regiment, it remained in service until its discharge at West Point on Nov.3, 1783.