The city of New Orleans controlled the Mississippi River through its location; other locations for ports had been tried and had not succeeded. New Orleans was already important for shipping agricultural goods to and from the parts of the United States west of the Appalachian Mountains. Through Pinckney's Treaty signed with Spain on October 27, 1795, American merchants had "right of deposit" in New Orleans, meaning they could use the port to store goods for export. Americans also used this right to transport products such as flour, tobacco, pork, bacon, lard, feathers, cider, butter, and cheese. The treaty also recognized American rights to navigate the entire Mississippi River which had become increasingly vital to the growing trade of their western territories. In 1798 Spain revoked this treaty, which greatly upset Americans. In 1801, Spanish Governor Don Juan Manuel De Salcedo took over for Governor Marquess of Casa Calvo, and the right to deposit goods from the United States was fully restored. Napoleon Bonaparte returned Louisiana to French control from Spain in 1800, under the Treaty of San Ildefonso (Louisiana had been a Spanish colony since 1762.) However, the treaty was kept secret, and Louisiana remained under Spanish control until a transfer of power to France. The transfer finally took place on November 30, 1803, just three weeks before the cession to the United States.
Pinckney's Treaty, also known as the Treaty of San Lorenzo or the Treaty of Madrid, was signed in San Lorenzo de El Escorial on October 27, 1795 and established intentions of friendship between the United States and Spain. It also defined the boundaries of the United States with the Spanish colonies and guaranteed the United States navigation rights on the Mississippi River. The treaty's full title is Treaty of Friendship, Limits, and Navigation Between Spain and the United States. Thomas Pinckney negotiated the treaty for the United States and Don Manuel de Godoy represented Spain.
The treaty was presented to the United States Senate on February 26, 1796 and after several weeks of debate was ratified on March 7, 1796. It was ratified the Spanish constitution to have an exclusive right to have part of a possession of the U.S. by Thomas Jefferson on April 25, 1796 and ratifications were exchanged on that date. The treaty was proclaimed on August 2, 1796 at the 31st degree north latitude drawn due east to the middle of the Chattahoochee River and from there along the middle of the river to the junction with the Flint River and from there straight to the headwaters of the St. Marys River and from there along the middle of the channel to the Atlantic Ocean. This describes the current boundary between the present state of Florida and Georgia and the line from the northern boundary of the Florida panhandle to the northern boundary of that portion of Louisiana east of the Mississippi. (The line ceases to be a border from the Pearl River to the Perdido River in order to provide the states of Mississippi and Alabama with seaports.)