Is Ellis Island in New York or New Jersey? Surprisingly, it’s in both. Under a 1934 compact, New York had jurisdiction over the original 3-acre Army fort, but the 24 acres of landfill that have since been added are part of New Jersey. The Supreme Court essentially upheld this arrangement in a 1998 ruling.

“New York still collects sales tax from concessions within the donut hole,” writes geographer Mark Monmonier, “while New Jersey taxes purchases elsewhere on the site.”