On 27 October 1795, at San Lorenzo el Real, Thomas Pinckney and Manuel de Godoy, Prince of the Peace, signed the Treaty of Friendship, Limits, and Navigation between Spain and the United States. The text is in English and Spanish. The American Senate consented on 5 March 1796; the American ratification is of 7 March, the Spanish of 25 April, at Aranjuez. Proclamation was on 2 August 1796.

Article I declares a firm peace. Article II draws the southern boundary on the 31st parallel, from the Mississippi due east to the middle of the Apalachicola (Catahouche), then the Flint, the head of the St Marys and the channel to the Atlantic. Troops in the other’s territory withdraw within six months. It is the 1763 line, not 32° 28′ which Spain claimed after British West Florida.

Article III sends one commissioner and one surveyor from each side to Natchez, within six months of ratification, to mark the line. Andrew Ellicott headed the American party. Ellicott’s Stone, on the 31st parallel in present-day Alabama, remains a marker of that work.

Article IV sets the western boundary in the middle of the Mississippi, to the 31st parallel, and opens navigation of the river, from source to ocean, only to Spanish subjects and American citizens. Article XXII gives Americans, for three years, the right of deposit at New Orleans, with no duty but the hire of stores; the king may continue it or assign an equivalent point on the bank.

Article V requires peace among the Indian nations on the lines: the Chickasaw and Choctaw fall, on the map, inside the United States. Spain will no longer arm tribes against the Americans. Articles VI–VII protect vessels and forbid embargo. In 1784 New Orleans had been closed to American goods coming down the river.

Congress organised the relinquished region as Mississippi Territory on 7 April 1798, with the capital at Natchez. The West Florida dispute reopened after San Ildefonso (1800) and the Louisiana Purchase. The 31° line is today the Florida–Georgia state line and, in stretches, Alabama and Mississippi.

The Avalon Project (Yale Law School) publishes the text: Treaty of Friendship, Limits, and Navigation Between Spain and The United States; October 27, 1795.

Image: BaronVonStrider, Ellicott's Stone (1799) on the 31st parallel, Alabama, CC BY-SA 4.0, Wikimedia Commons. Cropped to 16:9.

Source consulted: Pinckney's Treaty. Treaty text: Treaty of Friendship, Limits, and Navigation Between Spain and The United States; October 27, 1795.