I c&p this from my post in a previous thread about Marble Hill:
NOT SO FAST EVERYBODY!
You have asked a question I am currently trying to get to the bottom of myself.
First, some background:
When a kink in the Harlem River was straightened in1895, fifty-two acres known as Marble Hill were severed off the northern tip of Manhattan Island. Shortly thereafter they were attached to the Bronx mainland with landfill. Despite the separation by water, many residents – and all the mapmakers – continued to regard Marble Hill as part of Manhattan Borough and therefore, New York County.
Bronx Borough President, James J. Lyons, would have none of it. In 1939 he stormed into Marble Hill and, planting the flag of the Bronx, declared it part of his borough. Alas, the mapmakers did not agree.
But the situation took a turn for the surreal in 1984 with the strange case of The People vs. Wayne Boyd.
Wayne Boyd was charged with second-degree murder. At his trial he challenged the qualifications of a prospective juror on the grounds that – because the juror lived in Marble Hill – she was not a resident of New York County where the case was being tried. (The juror herself volunteered that her phone number was listed in the Bronx phone directory – an admirable, if not entirely persuasive argument.)
The court took the challenge seriously. After an exhaustive examination of the legal record – going back to colonial days – Justice McQillan declared that Marble Hill is indeed part of Manhattan Borough, but Bronx – not New York – County. He had found that Manhattan Borough was defined by law as including the Marble Hill territory; but Bronx County was defined by law as the territory north of MANHATTAN ISLAND. That put Marble Hill in Bronx County.
While I know that the court decision was never appealed, I must confess that I can’t definitively state that it was never reversed by some subsequent legislation (like the new NYC charter).
EVERYONE I’ve spoken with, EVERY map I’ve seen, and EVERY written reference I’ve found smugly declares MH to be part of Manhattan Borough AND New York County… but NONE of the “experts” I talked to had ever heard of the Wayne Boyd decision! So they may be just coasting on old, inaccurate information.