Did you know that the states of Pennsylvania and Connecticut have fought three wars with each other, one of which was after American independence? Not many people know this, but the Pennamite-Yankee Wars really happened.
The reason for these forgotten conflicts was that different British monarchs granted the same areas of what is now northern Pennsylvania to both Pennsylvania and Connecticut, resulting in conflicting land claims. “Yankees” from Connecticut moved in to settle the area, but so did “Pennamites” from Pennsylvania. It didn't take long before the two sides were shooting at each other, and then the militias of the rival colonies got in on the act.
The whole thing got muddled up with the War of Independence, so participants in the Pennamite-Yankee War were also involved in the revolution. After the war ended, the Yankees in Pennsylvania tried to secede and form their own State of Westmoreland with the help of Vermont's Ethan Allen. The whole thing was only resolved when the government eventually ruled in favor of Pennsylvania's claim to the Wyoming Valley, while also confirming the land claims of the Yankee settlers so they wouldn't lose their farms. The Pennamite-Yankee Wars weren't very bloody as wars go, but they were actual shooting wars with battles and fort sieges and even a “death march.”
Now don't you wonder why this one always gets left out of the history books? If we want kids to take an interest in history, shouldn't we be telling them about stuff like this?