The Mississippi Territory is organized by the United States, from territory ceded by Georgia and South Carolina; it will later be twice expanded, to include disputed territory claimed by both the U.S. and Spain (which has acquired territory in trade with Great Britain).

Natchez, established by French colonists in 1716, is one of the oldest and most important European settlements in the lower Mississippi River Valley.

After the French lost the French and Indian War (Seven Years' War), they had ceded Natchez and near territory to Spain in the Treaty of Paris of 1763. (It has later traded other territory east of the Mississippi River with Great Britain, which expanded what it called West Florida).

The United States having acquired this area from the British after the American Revolutionary War, the city serves as the capital of the Mississippi Territory.

President John Adams appoints Winthrop Sargent the first governor, effective from May 1798 to May 1801.

Appointed by the Congress of the Confederation as the first Secretary of the Northwest Territory, a post second in importance only to the governor, Arthur St. Clair, Sargent had taken up his post in 1788.

Like St. Clair, Sargent has functioned in both civil and military capacities; he had been wounded twice at the Battle of the Wabash, on November 4, 1791.

He also served in the Indian wars of 1794-5 and became adjutant general.

On August 15, 1796, as Acting Governor, he had proclaimed the establishment of Wayne County, the first American government in what is now Michigan.

His last entry as Northwest Territory's secretary is on May 31, 1798; he arrives at Natchez on August 6, but due to illness is unable to assume his post until August 16.