Most of the English colonies in Atlantic North America were founded by people pretending to go as far as possible from England, where they pretended to live with as little control from English authorities as possible.
The land they chose was however surrounded by other Europeans trying to impose their own institutions, and by heathen savages. English institutions were bearable in comparison. But after the war, the French were no longer a threat in Canada, and soon the British authorities begun to look unbearable. Mainly because British authority —and taxes— was imposed from Westminster where no American had the possibility to say.
The Spanish in Florida and the Indians were controllable threats for the United Colonies, and in June 22, 1776, representatives of the colonies subscribe a Declaration of Independence.
Not all colonies participated. Not all colonies had the same expectations and in many places the loyalty to the English/British institutions was greater than the desire not to be bothered. New Brunswick, Nova Scotia, Newfoundland shared this view. The former French territories of Canada and Louisiana had been developed by a different sort of Anglo colonial: people who identified themselves as British rather than American, and settlers of French origin who would rather have a royal institution overseas that respected their autonomy, than a bully local government. In the territories of Transylvania people were more kind to the independent colonists, but it was the British who granted them autonomy.
Soon a war started. Britain would not allow the colonies to leave. Colonial leader Washington had already drawn up a plan: to prove in battle they are worth a nation and get external powers to recognise the new nations, and who else would those external powers be but France and her underdog: Spain.
The deal was simple, France help the Americans fight the English and the new American nations would back France in getting Louisiana back. And, after all, who is not prepared to an after-match ?
The Americans resisted long enough until they got France and Spain involved, but in the Gulf of Mexico, France was barely a support to the real actors. There were the Spanish who besieged and captured New Orleans, and who raided up the Mississippi destroying a few British outposts.
The Spanish had no possible power in controlling Louisiana during the war. Many loyalists in the Southern colonies moved westward and the English had a few military outposts far enough from the Mississippi to survive the initial raid. When the Spanish were busy capturing Bahamas, the British captured Baton Rouge and besieged New Orleans.
In 1783 the war was over, and the second Treaty of Paris acknowledged this. The United States of America were recognised by the other signing powers. Britain kept Louisiana and the territories between the Mississippi and the Appalachians, south of the Ohio River and North of the 31 parallel, and Spain kept Florida. France was returned a few islands in the Caribbean and a joint control of St Domingue.