However, if this field is not meaningful, that is it is strictly for the database to internally identify a unique record, it is a surrogate key or blind key. In this case Person ID probably is an AutoNumber field, and it should not be used except internally by the database.
It's the city of New York that is divided into boroughs. In 1898, the modern city of New York was formed by merging the County of New York (modern day Manhattan and the Bronx), the then independent city of Brooklyn, Richmond County, and the western parts of then Queens County (the remainder is modern day Nassau County). To make people happy, the new city was divided into boroughs (similar to London). The original city of New York became Manhattan (named after the island it is on). The remainder of New York County became The Bronx. Brooklyn stayed Brooklyn. Queens County is also Queens. And Richmond County became Staten Island (also named after the island it is on).
New York City encompasses five different county-level administrative divisions called boroughs: Manhattan, the Bronx, Queens, Brooklyn, and Staten Island. All boroughs are part of New York City, and each of the boroughs is coextensive with a respective county, the primary administrative subdivision within New York State. The Bronx and Queens are concurrent with the counties of the same name, while Manhattan, Brooklyn, and Staten Island correspond to New York, Kings, and Richmond Counties respectively.