Ohio and Michigan fought a war over the strip of land containing Toledo.

The Northwest Ordinance would begin the disagreement between Ohio and Michigan because it set the border from the tip of Lake Michigan across the bottom of the peninsula running east to west. 

This caused a strip of land that Ohio formerly laid claim to, to be officially considered Michigan land. Because of inaccuracies in maps, originally neither side noticed that Toledo would be included in Michigan. 

It would be a few years later before Michiganders recognized that area as their own, angering Ohioans. In December 1833, Michigan applied to join the Union, but Ohio blocked their attempt, making it difficult for them to join until they agreed to let Ohio have the area. What resulted was initially a political war. Michigan promised to fine any Ohio officers trying to act in the Toledo strip. Ohio responded by appointing sheriff and judge to act in the area. 

Then, Michigan “governor” Stevens T. Mason mobilized troops against Ohio. It only got worse from there with Ohio approving a $300,000 military budget, while Michigan countered with a $315,000 military budget. The actually “war” resulted in Michigan arresting several Ohio officers and one Ohio stabbing a Michigan sheriff in a pub fight. 

President Jackson then stepped in to end the fighting. Ohio ended up with the Toledo strip, and Michigan gained statehood and a resource-rich piece of land. 

(Source)