Why is part of Kentucky north of the Ohio River?

Kentucky's border follows the Ohio River where it ran in 1792, when Kentucky became a state. The river later moved, so a piece of Kentucky near Evansville, Indiana, where Ellis Park racetrack stands, ended up on the Indiana side. The Supreme Court confirmed it belonged to Kentucky in Indiana v. Kentucky in 1890.

Why is Washington DC not a square?

DC was laid out as a 10-mile square, part of it taken from Virginia. In 1846 Congress returned the Virginia side, including Alexandria, to Virginia, leaving the District with its current shape.

Who owns the Connecticut River between Vermont and New Hampshire?

New Hampshire. The Supreme Court ruled in Vermont v. New Hampshire in 1933 that the border is the low-water mark on the Vermont side of the river.

Borders that make no sense.

Rivers make convenient borders until they move. Squares stay squares until someone wants their land back. Three American borders that look like mistakes, and are not.

A Timeless Tales story · 4 minute read

The short version, from my channel. Watch it on YouTube.

Correction: the video places the stranded piece of Kentucky next to Ohio. The best-known case is actually on the Indiana side of the river, near Evansville.

Kentucky's river that moved

When Kentucky became a state in 1792, its northern border was set at the low-water mark on the far side of the Ohio River. That means Kentucky owns the river itself, and the line is frozen where the river ran in 1792, not where it runs today.

Rivers move. Near Evansville, Indiana, the Ohio shifted south, and a former island ended up joined to the Indiana bank. It is still Kentucky. The Supreme Court settled it in Indiana v. Kentucky in 1890, and today Ellis Park racetrack sits on that piece of Kentucky, north of the river.

Washington DC's missing corner

The capital was planned in 1790 as a perfect square, ten miles on each side, turned on its point like a diamond. Maryland gave the land on one side of the Potomac, Virginia the land on the other, including the town of Alexandria.

The Virginia side never got much from the federal government, and its residents wanted their state back. In 1846 Congress agreed, and the land south of the Potomac was returned to Virginia. That is why today's DC looks like a square with a bite taken out of it.

Vermont's river it does not own

Vermont and New Hampshire are divided by the Connecticut River, but the line does not run down the middle. In Vermont v. New Hampshire, decided in 1933, the Supreme Court ruled that the border is the low-water mark on the Vermont bank. The whole river is in New Hampshire.

1790 DC laid out as a 10-mile square
1792 Kentucky's border fixed at the Ohio River of that year
1846 The Virginia side of DC is returned
1890 Indiana v. Kentucky
1933 Vermont v. New Hampshire

Sources

Indiana v. Kentucky, 136 U.S. 479 (1890), Justia
Part of Kentucky's border is north of the Ohio River, FOX 56 News
Ellis Park Race Course, Wikipedia
District of Columbia retrocession, Wikipedia
Vermont v. New Hampshire, Wikipedia