The story behind this one is bizarre by our standards, yet mundane by 19th century standards.
It's (kind of) common knowledge in Wisconsin that what is now Michigan's upper peninsula was once part of America's dairyland, and was somehow ceded to our eastern neighbors. But just like most common knowledge, this isn't quite as true as it seems. It's actually the result of a war which had nothing to do with Wisconsin. And not the "aggressive diplomacy" sort of war. A sheriff was stabbed, so we're going to count it as a war.
The inaccurate "Mitchell Map" started a border dispute, an interstate "war," and decided the fate of the UP.
In the 18th century, cartography wasn't an exact science and statelines weren't something you could look up on Google maps. In 1787, the U.S. government enacted the Northwest Ordinance, declaring the border between the state of Ohio and Michigan Territory as "an east west line drawn through the southerly bend or extreme of Lake Michigan." Congress used the Mitchell Map to define this line, and as you can tell from looking at the map above, Mitchell was a bit off in his calculations. A straight line drawn with the US government's description would have cut off almost all of Ohio's access to Lake Eerie, which would have cost Ohio a lot of trade revenue. To avoid this, Ohio changed the description of the border itself so that it ran from Lake Michigan to Maumee Bay.
So far so good, until Michigan applied for statehood in 1833 and drew the border between itself and Ohio using an accurate map and the original description of the border. This created a tract of land called the "Toledo Strip," 5 to 8 miles wide. To try and make Michigan give the land back, Ohio governor Robert Lucas pulled some favors in congress to deny Michigan's statehood. Enraged, Michigan governor Stevens Masons enacted the "Pains and Penalties" act making it an imprisonable offense to support Ohio in the Toledo Strip, and enforced it sending 1,000 Michigan militia to the strip. In response, Lucas sent 600 Ohio militia.
No Man's Land. I think I can hear Ennio Morricone music in the background.
Okay so the Toledo "War" wasn't that exciting; it was mostly bloodless skirmishes, arrests, lawsuits, and saber rattling. There was one bizarre case where Michigan sheriff Joseph Wood tried to arrest Major Benjamin Stickney for voting in an Ohio election while living in the strip. Benjamin and his sons, One Stickney and Two Stickney (you can't make this up), resisted and stabbed the sheriff. He survived his wounds, and it was enough to prompt both sides to withdrawn from the No Man's Land. The political scuffle went on until 1836 when a deal was reached. Michigan would gain statehood and give up the Toledo Strip, but gain the upper peninsula from the Northwest Territory. Ohio considered it a victory.
That is until people learned about the mountains stuffed full of copper and iron ore in the upper peninsula. More wealth came out of the UP than out of California during the gold rush, and supplied 90% of America's iron and copper. Sounds like Michigan got the better end of the deal.
In the summer of 1837, as the Toledo War was ending and Michigan was gaining its statehood, the Wisconsin territory was officially formed. Wisconsin was, at one point, part of Michigan territory but broke off before it ever had its own name on the upper peninsula. Thus, we never had it. But, if Ohio had just kept to itself and accepted the loss of the Toledo Strip, Michigan would have likely left the upper peninsula for Wisconsin.