Geographically, this little neighborhood—which supplied the city with prime Inwood marble used to construct many landmark buildings—is connected to mainland United States.
You’d think it was in the Bronx. But it’s officially part of Manhattan.
This map weirdness happened when the city enlarged the Harlem River ship channel in 1895. That turned Marble Hill—then at the northernmost tip of Manhattan, separated from the Bronx by Spuyten Duyvil Creek—into an island, with the Harlem River on its north and the creek to the south.
[A 1916 NYPL map of Upper Manhattan; Marble Hill a bump at the top]
In 1914, the creek was filled in, cleaving Marble Hill to the Bronx, though it was declared Manhattan territory in 1897.
Over the years, which borough it belonged to was brought into question. In 1939, the Bronx borough president planted a Bronx flag at Marble Hill and demanded that all residents submit to Bronx rule—a really bad joke met with resounding boos by dozens of Marble Hill residents.
In 1984, it was settled: the neighborhood is in Manhattan—albeit with a 718 area code, a Bronx zip code, and kind of a split identity.