The Middle Department was established on February 27, 1776. Originally 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.