On December 12, 1800, Washington became the capital of the United States. As early as 1788, James Madison emphasized the need for a federal district in his essay “The Federalist No. 43,” arguing that the nation’s capital needed to be distinct from the states to ensure its own support and safety.
An attack on the convention in Philadelphia by a mob of angry soldiers, known as the Pennsylvania Rebellion in 1783, underscored the need for government to provide for its own security. Therefore, the right to establish a federal capital is provided for in Article One, Section Eight of the United States Constitution, which allows “a county (not exceeding ten square miles) to become the seat of the government of the United States by the cession of territories of certain states and congressional approval”.
However, the constitution does not specify a place for the new capital. Madison, Alexander Hamilton, and Thomas Jefferson agreed that the federal government would accept the assumption of the war debt by the states on the condition that the new capital is located in the southern United States, which later became known as the Compromise of 1790.
On July 16, 1790, the Residence Act decreed that the new capital would be located permanently along the Potomac River, the exact area to be chosen by President Washington. The original shape of the federal district was a square measuring 16 km (10 mi) on each side, for a total of 260 km (100 sq mi), as allowed by the US Constitution.
In 1791-1792, Andrew Ellicott and several associates measured the county boundary around Maryland and Virginia, placing stones every mile.
A new “federal city” was built on the north bank of the Potomac River east of the established settlement of Georgetown. On September 9, 1791, the “federal city” was named in honor of George Washington and the district was declared the Territory of Columbia, used as a poetic name for the United States at the time. Congress held its first session in Washington on November 17, 1800. On December 12, 1880, Washington became the capital of the United States.
The 1801 act formally incorporated the cities of Washington, Georgetown, and Alexandria, making them part of the federal territory of the District of Columbia, placing it solely under the control of Congress. Also, the territory in the county is divided into two: Washington County – to the east of the Potomac River and Alexandria County – to the west. After this act, citizens in the district were no longer considered residents of Maryland or Virginia, thus ending their representation in Congress.