The metropolitan New York City has the word's most significant concentration of Jewish religious, cultural and social institutions. This is no wonder considering the 1 million or so Jews living in Greater New York area.
Jewish life of New York is most vibrant in Manhattan and obviously Brooklyn there are several parts of Brooklyn where various ultra-orthodox communities reside: Boro Park, Williamsburg and Crown Heights being the better-known ones. Lower East Side of Manhattan is also heavily Jewish.
Large part of Manhattan is within the Manhattan Eruv: all of the Central Park, Sutton Place, Upper East Side, Yorkville, Upper West Side, East Midtown (from 6th Ave eastwards) and all the way to the 11th Street.
In Brooklyn, congregation B'nai Avraham constructed an eruv comprising the Brooklyn Heights and other neighborhoods to the south-east. Flatbush and Boro Park have also interconnected eruvim accepted by many but not all rabbinic authorities.
New York's kosher hotel, The Avenue Plaza, is located on the 13th Avenue, in the centre of Boro Park.
Jewish New York is central to Jewish life in North America and it hosts the headquarters of most American and international Jewish institutions and organizations.