Born in Oporto, Portugal, on May 30, 1747, to Spanish consul Manuel Luis Gayoso de Lemos y Sarmiento and Theresa Angélica de Amorín y Magallanes, he received his education in London, where his parents were living.

At age 23 Manuel Gayoso de Lemos joined the Spanish Lisbon Regiment as a cadet (1771), and he was commissioned ensign (sub-lieutenant) the following year.
The Lisbon Regiment had been reassigned from Havana to New Orleans following since Spain assumed control of Louisiana under Field Marshal Alejandro O'Reilly in 1769.
Throughout his life, Gayoso de Lemos retained his military rank and he was a brigadier at the time of his death.

On November 3, 1787, Gayoso de Lemos assumed military and civil command of the fort and the newly organized Natchez District, having been appointed district governor by Governor-General Esteban Rodríguez Miró following the defeat of the British in West Florida.
On his arrival, Gayoso de Lemos established an informal cabildo (council) of landed planters, which was formalized in 1792.
Most of the council were of non-Spanish origin having come down from the Ohio River Valley settlements (especially Kentucky).
Gayoso de Lemos continued to encourage American settlement on Spanish soil, especially by Catholics, notably the Irish and the Scots, and by those who brought significant property.
He moved the administrative part of the town of Natchez from the waterfront up onto the bluff.
One of the most troubling aspects during his civil administration was confusion in the land titles, with a number of inconsistent land grants.
Unfortunately, Rodríguez Miró's successor, Governor-General Francisco Luis Héctor de Carondelet was not amenable to rectifying the problem.

While in Natchez, Gayoso de Lemos used the greed of a number of Americans, notably General James Wilkinson and Philip Nolan, to help limit the growth of the United States.
Also to this end, Gayoso de Lemos entered into alliances with local Native American tribes and signed formal treaties with them, most notably the 1793 Treaty of Nogales establishing offensive and defensive alliances with the Chickasaw, Muscogee, Talapuche, Alabama, Cherokee, and Choctaw nations.
Under his direction the Spanish fortified the Mississippi at Fort Nogales (later Walnut Hills, then Vicksburg) and Chickasaw Bluffs (later Memphis).
He was instrumental in acquiring the information from Wilkinson concerning the proposed U.S. attack on New Orleans in 1793 by General George Rogers Clark.

However, under the terms of Pinckney's Treaty in 1796, Spain agreed to relinquish the Natchez District to the United States.
Gayoso de Lemos oversaw the gradual Spanish withdrawal from the east side of the middle Mississippi River.
In March 1797, the Fort Nogales was decommissioned, with the troops and stores being moved to St. Louis.
Final evacuation of the district did not occur until 1798, at which time the U.S. established the Mississippi Territory.
Born in Oporto, Portugal, on May 30, 1747, to Spanish consul Manuel Luis Gayoso de Lemos y Sarmiento and Theresa Angélica de Amorín y Magallanes, he received his education in London, where his parents were living.
At age 23 Manuel Gayoso de Lemos joined the Spanish Lisbon Regiment as a cadet (1771), and he was commissioned ensign (sub-lieutenant) the following year. The Lisbon Regiment had been reassigned from Havana to New Orleans following since Spain assumed control of Louisiana under Field Marshal Alejandro O'Reilly in 1769. Throughout his life, Gayoso de Lemos retained his military rank and he was a brigadier at the time of his death.
On November 3, 1787, Gayoso de Lemos assumed military and civil command of the fort and the newly organized Natchez District, having been appointed district governor by Governor-General Esteban Rodríguez Miró following the defeat of the British in West Florida. On his arrival, Gayoso de Lemos established an informal cabildo (council) of landed planters, which was formalized in 1792. Most of the council were of non-Spanish origin having come down from the Ohio River Valley settlements (especially Kentucky). Gayoso de Lemos continued to encourage American settlement on Spanish soil, especially by Catholics, notably the Irish and the Scots, and by those who brought significant property. He moved the administrative part of the town of Natchez from the waterfront up onto the bluff. One of the most troubling aspects during his civil administration was confusion in the land titles, with a number of inconsistent land grants. Unfortunately, Rodríguez Miró's successor, Governor-General Francisco Luis Héctor de Carondelet was not amenable to rectifying the problem.
While in Natchez, Gayoso de Lemos used the greed of a number of Americans, notably General James Wilkinson and Philip Nolan, to help limit the growth of the United States. Also to this end, Gayoso de Lemos entered into alliances with local Native American tribes and signed formal treaties with them, most notably the 1793 Treaty of Nogales establishing offensive and defensive alliances with the Chickasaw, Muscogee, Talapuche, Alabama, Cherokee, and Choctaw nations. Under his direction the Spanish fortified the Mississippi at Fort Nogales (later Walnut Hills, then Vicksburg) and Chickasaw Bluffs (later Memphis). He was instrumental in acquiring the information from Wilkinson concerning the proposed U.S. attack on New Orleans in 1793 by General George Rogers Clark.
However, under the terms of Pinckney's Treaty in 1796, Spain agreed to relinquish the Natchez District to the United States. Gayoso de Lemos oversaw the gradual Spanish withdrawal from the east side of the middle Mississippi River. In March 1797, the Fort Nogales was decommissioned, with the troops and stores being moved to St. Louis. Final evacuation of the district did not occur until 1798, at which time the U.S. established the Mississippi Territory.
Manuel Gayoso de Lemos