FWIW, I grew up near the western shore of the Red River which marks the boundary between North Dakota and Minnesota. When the Army Corps of Engineers made some channels in the oxbow to speed the flow of the river in the 1930s, it actually took an Act of Congress to recognize the new boundaries. North Dakota gained a few acres of territory overall.
No such act was passed when the Mississippi River changed course and, as a result, there is actually quite a substantial part of Illinois on the Missouri side of the river today as opposed to the reverse. As a result, Kaskaskia, the old Illinois Territorial Capital is on the Missouri side of the river today.
Yes.
Maybe it was Massachusetts. :-)
Distantly related: We were traveling through Canada when they went metric. One radio DJ commented that a lady called in and asked if the winters would be colder under the new system.