Territorial Evolution of The United States - 18th Century

18th Century

March 4, 1789

The United States Constitution came into effect, forming the new nation. Note that the states ratified at different times, but to simplify the map, the final result is shown here.

The United States achieved independence from the Kingdom of Great Britain with the Treaty of Paris on September 3, 1783, which established that the thirteen colonies were sovereign and independent states. The borders were established by Article 2 of the treaty, but with a couple of issues. First, it stated that the border would run west from the Lake of the Woods to the Mississippi River - at the time, it was not known that the headwaters of the Mississippi lay south of such a line, so the border has since been taken to run south from the lake to the river.

Some peculiarities to point out to those familiar only with the current borders: Many states had sea-to-sea grants from the British crown that they would not give up easily, so prior to this date, they ceded this land to the federal government in exchange for their Revolutionary War debts. However, Georgia did not do so until much later, and Connecticut ceded most land but kept its Western Reserve. Virginia ceded its claim to the territory north and west of the Ohio River, and this land became unorganized territory. North Carolina also ceded its claim to its western counties, but this was not officially accepted by Congress until 1790. New York ceded its claim on the Erie Triangle to the federal government. At this point in history, all of the states except for Georgia and Virginia were at their present-day borders, except for some of the minor issues mentioned above.

West Florida claimed a border further north than what the United States said it had. Its border had been 31° north when Spain ceded it to the United Kingdom. The British later moved its border north to 32°38′ latitude, but when Spanish Florida was ceded back to Spain in the Treaty of Paris, the British cited the original border at the 31st parallel north, but Spain continued to claim the higher border. Also, the borders at the northern area of the Maine District of Massachusetts and the area northwest of Lake Superior remained disputed.

The Wedge, disputed since the 17th century, remained a point of contention between Delaware and Pennsylvania.

The Vermont Republic was a complex matter, with areas being claimed by New York and New Hampshire, but it existed as a de facto unrecognized independent state.

August 7, 1789

The United States Congress affirmed the organization of the Territory North West of the Ohio River, or Northwest Territory, under the terms of the Northwest Ordinance. Northwest Territory consisted of present-day Illinois, Indiana, Michigan, northeastern Minnesota, most of Ohio, and Wisconsin. The Northwest Territory had previously been organized under the Articles of Confederation on July 13, 1787, and was slightly modified under the new Constitution.

April 2, 1790

Congress accepts North Carolina's cession of its western counties, which had initially been ceded on December 22, 1789. The land became unorganized territory.

May 26, 1790

The Southwest Ordinance organized the Territory South of the Ohio River, or Southwest Territory, which corresponded to present-day Tennessee.

March 4, 1791

The Vermont Republic, which had portions claimed by New York and New Hampshire and, while unrecognized by the United States, was a de facto independent country, was admitted as the 14th state, Vermont.

September 9, 1791

The District of Columbia, the nation's federal district, was formed from land granted by Maryland and Virginia; the Virginia portion would be returned in 1847.

March 3, 1792

The federal government sold the Erie Triangle to Pennsylvania.

June 1, 1792

The western counties of Virginia beyond the Appalachian Mountains were split off and admitted as the 15th state, Kentucky.

January 11, 1794

In the third Nootka Convention Spain surrenders its exclusive claim to the entire Pacific Coast and acknowledges the right of Britain or other powers to use unoccupied territory.

October 27, 1795

Pinckney's Treaty, also known as the Treaty of San Lorenzo, signed on October 27, 1795, and proclaimed on August 3, 1796, settles the northern border of West Florida as the 31st parallel.

June 1, 1796

The Southwest Territory was admitted as the 16th state, Tennessee.

April 7, 1798

Due to the Yazoo Land Fraud, an act was signed by President John Adams, authorizing him to appoint commissioners to negotiate with Georgia about ceding its western land. The act created Mississippi Territory in the region ceded by West Florida, corresponding to roughly the southern third of present-day Mississippi and Alabama except their panhandles, which were part of West Florida.