Certainly, the British government used to control the thirteen original colonies, and though you may have thought that the Revolutionary War (and the War of 1812) solved that conundrum, according to some you would be wrong.
It seems that the southern sections of Mississippi, Alabama, Florida, and Louisiana are technically “the Dominion of British West Florida” according to the Treaty of 1763, signed by the kingdoms of Great Britain, France, and Spain with Portugal.
In June of 1810, many who resented Spanish rule across the region held meetings in Baton Rouge. These meetings evolved into an outright revolt known as the West Florida Rebellion. Participants were fully intent on establishing an independent country with its capital as St. Francisville. That September, rebels took Fort Carlos and raised their own flag, establishing the Republic of West Florida. The rebellion moved on to attempt to take Mobile and Pensacola from Spanish control. The plan failed. Although the new republic had elected a governor, Fulwar Skipwith, constant pressure from Washington D.C. ended the rebellion. President James Madison had signed the “Annexation by Proclamation” that revoked the land from the Spaniards and claimed it as American soil. By the year’s end, West Florida’s last flag peacefully came down.
Not long after the proclamation was signed. There were a few ensuing battles, but the Spaniards were pushed from the land totally by 1813. The United States government paid Spain for the land, but never acknowledged that the British had some claim to the land, too. It is historically unclear if the British thought they had some claim to it either.
In 2005, the Third Restoration effort was begun on the World Wide Web (it is somewhat unclear who is behind it), to petition the Queen of England to recognize British West Florida. Currently, the British government refuses to acknowledge the individuals claiming to represent the Dominion, as any claim would disrupt relations between Great Britain and America.