Park Slope is a neighborhood in western Brooklyn, New York City, within the area once known as South Brooklyn. Park Slope is roughly bounded by Prospect Park and Prospect Park West to the east, Fourth Avenue to the west, Flatbush Avenue to the north, and Prospect Expressway to the south. Generally, the section from Flatbush Avenue to Garfield Place is considered the "North Slope", the section from 1st to 9th Street is considered the "Center Slope", and south from 9th Street, the "South Slope". The neighborhood takes its name from its location on the western slope of neighboring Prospect Park. Fifth Avenue and Seventh Avenue are its primary commercial streets, while its east–west side streets are lined with brownstones and apartment buildings.

Brooklyn is a borough of New York City. Located on the westernmost end of Long Island, it is coextensive with Kings County in the U.S. state of New York. With 2,736,074 residents as of the 2020 United States census, Kings County is the most populous of the five boroughs of New York City and the most populous county in the State of New York. The population density of Brooklyn was 37,339.9 inhabitants per square mile (14,417.0/km2) in 2022, making it the second-most-densely-populated county in the United States, behind Manhattan, and it had the ninth-highest population of any county nationwide. Were Brooklyn still an independent city, it would be the fourth most populous in the U.S. after the rest of New York City, Los Angeles, and Chicago.