We have America because of Alabama (You're welcome)

It's the 1740s in colonial British America. You notice that thriving cities and industries have sprung up in the New World, there's beginning to be serious sustainable population and infrastructure. Also, you don't really like the British. Even though they technically own everything due to aristocratic deals with the King, most of the Europeans are actually there to get away from the royal government or European societies in some form.

There are problems with forming an independent country though. You can't economically support a war effort or an independent country thereafter without a sustainable transportation and import/export system. In the 1700s, or any time before industrialized railroads, automobiles, and planes, you need the Mississippi River and New Orleans to support a North American nation. There's no other way around it.

Now draw a direct line from the British colonial cities to New Orleans. It goes straight through that neutral gap between colonial England and colonial France. That includes more navigable waterways and rivers than any other part of the continent through the Ohio River Valley, the Cumberland Gap, down the foothills and the richly fertile plains of southern Alabama and Georgia. It is prime real estate. It is perfect for settlements, farms, and (probably most importantly) direct inland river transportation from cities to the Gulf.

So you want a new country, but you're in a pickle. You can't go to war with France to take the necessary land without British military help or consent. You can't rebel against the British because the French will snatch up this land while you're facing the other direction.

Luckily, the Seven Years War breaks out. The great powers in Europe are in a war as usual with England and France on opposite sides as usual. French and English colonists in America are paranoid of each other and are sending out expeditionary forces to protect the neutral land. Of course, as an American who wants this land, you decide to portray this to the British as a French invasion, the western theater of the great war in Europe. Doesn't really matter if it's true or not, now the British are coming to defend you, they beat the French for you, drive them out of North America almost entirely, and hand you the land you need. The French and Indian War.

Now every problem is solved. You have the land and geography you need to support a war effort and a new country. And you can go to war with your British colonizers without leaving it vulnerable to the French colonizers. And a few years later, that's exactly what happened.