The 1795 War
Long periods of peace were an abnormality between Spain and England/Britain, and after the Seven Years War and the Spanish-American war there were many armed confrontations, from border skirmishes to two open wars: the American Independence War and the War of 1795.
The war of 1795 started shortly after the Spanish-French agreement and its causes included rising tensions on the Louisiana-Florida border, the status of French colonies, and Britain's new policy on slavery.
As part of the Spanish-French Peace Agreement of 1792, Spain would provide means for the French to enforce the sovereignty of several French colonies and French possessions on the Mediterranean. This led to increasing tensions between Britain and Spain.
The spark came from the Mississippi, however. Baton Rouge and New Orleans were too close to each other and both had some control over what came through the Mississippi. Tensions were rising as both Spain in Baton Rouge and Britain in New Orleans registered each others' ships. This registering increased as more people were settling in western Florida, demanding slave labor while the new British policy attempted to stop traffic of enslaved born-free Africans into their North American territories (mainly Louisiana and Transylvania).
It was common knowledge that many slaves had been brought from Africa into plantations in Transylvania, pretending that they came to Spanish territory, so the British increased their controls. The Spanish authorities in Baton Rouge applied a reciprocity policy. When the Spanish demanded a British military vessel submit for registry, the HMS ship emptied her guns against the fortifications of Baton Rouge and sailed back to New Orleans.
The Spanish invaded New Orleans and by late 1795 the war was fought in most scenarios over Spanish and British interests, with revolutionary France giving nominal support to the Spanish and the Portuguese allying to the English.
Despite constant battles the intensity of the combat, with a few exceptions, were much milder than the two previous wars. The British captured Baton Rouge and San Juan (but could not control the island). The Spanish had managed to capture the Bahamas, Georgetown, and Belize, and in a naval battle to break the blockade of Gibraltar, most of the French fleet and an important part of the Spanish fleet was sunk, as well as a great deal of the British fleet, including the flag ship.
In the summer of 1797, Spain, Britain, France and Portugal signed the Lisbon Peace Agreement, recognizing full Spanish control in Central America, and the end of British presence in South America, and the return of San Juan. Spain would cede Baton Rouge and surrounding territories to Britain (keeping Mobile and the rest of Florida), return the Bahamas, and de-occupy Portuguese territory in Europe (but was permitted to keep Uruguay, Rio Grande do Sur and Spiritu Santo). Gibraltar would remind British. Britain would occupy and administer any French colonies in the Caribbean (but would still have status as French colonies).
With Baton Rouge in her hands, Britain now had complete control on the Mississippi.