it included all of the colonies of New York, New Jersey, Pennsylvania, Delaware, and Maryland. In April 1776, the Main Army moved from Boston to New York, and became the field army associated with the Middle Department for the remainder of the war. On April 14, 1776 that portion of New York north of the Hudson Highlands, and the present state of Vermont were separated from the Middle Department and organized as the Northern Department. The Middle Department then comprised the Hudson Highlands in the state of New York, the rest of New York south of the Highlands, and the states of New Jersey, Pennsylvania, Delaware, and Maryland. The term Main Army had come into use during the Siege of Boston, because the majority of Continental Army regiments were assigned to it. The term was retained throughout the war. Most units in the Middle Department were assigned to the Main Army, under George Washington, or to the Highlands Department, which was under Washington's close supervision. A few regiments and independent companies were assigned to the Middle Department from time to time, but were not assigned to Washington's army or to the Highlands. These units were simply said to have been assigned to the Middle Department. Some of the Continental Army's most important campaigns were fought in this department. These included the New York campaign and the New Jersey campaign which ended with the battles of Trenton and Princeton. The Philadelphia campaign was fought in this department, after which the Continental Army went into winter quarters at Valley Forge. In 1778 this department was the scene of the Monmouth campaign. After Monmouth, on June 28, 1778, major military operations in the United States shifted to the Southern Department. The department existed until the close of the war. It was the scene of one of the war's last episodes when the British Army evacuated New York City on November 25, 1783. Western Department The Western Department covered the frontier territories west and northwest of Virginia and Pennsylvania, including the present states of Ohio, Indiana, Illinois, Michigan, and Wisconsin. It extended from Pittsburgh all the way to the Illinois country and as far north as the southern peninsula of Michigan. The department was established in 1777. Its first commander was Edward Hand. George Rogers Clark's Illinois campaign of 1779 was one of the most notable operations in this department. This department was the