Louisiana, or the Province of Louisiana, was a province of New Spain from 1762 to 1801 primarily located in the center of North America encompassing the western basin of the Mississippi River plus New Orleans. The area had originally been claimed and controlled by France, which had named it La Louisiane in honor of King Louis XIV in 1682. Spain secretly acquired the territory from France near the end of the Seven Years' War by the terms of the Treaty of Fontainebleau (1762). The actual transfer of authority was a slow process, and after Spain finally attempted to fully replace French authorities in New Orleans in 1767, French residents staged an uprising which the new Spanish colonial governor did not suppress until 1769. Spain also took possession of the trading post of St. Louis and all of Upper Louisiana in the late 1760s, though there was little Spanish presence in the wide expanses of what they called the "Illinois Country".

New Spain, officially the Viceroyalty of New Spain, originally the Kingdom of New Spain, was an integral territorial entity of the Spanish Empire, established by Habsburg Spain. It was one of several domains established during the Spanish conquest of the Americas, and had its capital in Mexico City. Its jurisdiction comprised a large area of the southern and western portions of North America, mainly what is now Mexico and the Southwestern United States, but also California, Florida and Louisiana; Central America, the Caribbean, and northern parts of South America; several Pacific archipelagos, most notably the Philippines and Guam. Additional Asian colonies included "Spanish Formosa", on the island now known as Taiwan.