Washington County, Maryland is included in the Hagerstown-Martinsburg, MD-WV Metropolitan Statistical Area, which is also included in the Washington-Baltimore-Arlington, DC-MD-VA-WV-PA Combined Statistical Area. The closes states to Washington County is west Virginia, Pennsylvania, Virginia, and Tennessee. The western portions of the Province of Maryland (including present Washington County) were incorporated into Prince George's County in 1696. This original county included six current counties. The first to be created was Frederick, separated from Prince George's County in 1748. Following independence, the sovereign State of Maryland formed Washington County on September 6, 1776, by the division of Frederick County. At the same time, a portion
Maryland of the American Revolutionary War (1775–1783), on February 2, 1781, Maryland became the last and 13th state to approve the ratification of the Articles of Confederation and Perpetual Union, first proposed in 1776 and adopted by the Second Continental Congress in 1778, which brought into being the United States as a united, sovereign and national state. It also became the seventh state admitted to the Union after ratifying the new federal Constitution in 1788. In December 1790, Maryland donated land selected by first President George Washington to the federal government for the creation of the new national capital of Washington,