Gerritsen Beach lies on a peninsula in the southeastern part of Brooklyn, near Marine Park; it is bounded on the north by Avenue U, to the east by Gerritsen Avenue, to the south by the Plumb Beach Channel, and on the west by Shell Bank Creek and Knapp Street. It is bisected, from west to east, by the Gotham Avenue Canal. The area north of the canal, known as the "new section" by local residents, has traditional city streets lined with stores, brick houses, and wide sidewalks. The area south of the canal (the "old section") retains the character of a mall fishing billage and is a popular spot for party boats and chartered fishing boats to be berthed.
Until the early twentieth century, the area remained undeveloped except for a few squatters' bungalows clustered at the foot of Gerritsen Avenue. In 1920, Realty Associates, a speculative real-estate builder, began constructing a middle-class summer resort there. The southwestern section of Gerritsen's meadows was soon covered by one-story bungalows with peaked roofs and no backyards; typically, these houses were built on tiny 40-by-45-foot lots. The popularity of this venture spurred futher growth. Some bungalow-owners made them suitable for year-round habitation:others built two-story houses with backyards; and within a decade, there wre fifteen hundred houses in Gerritsen Beach. with its narrow streets and closely-bunched homes (some sitting direclty at the water's edge), this neighborhood in south Brooklyn is often linked to a New England fishing village.
The neighborhood has residents of many different races and ethnic backgrounds, but there is a large Irish-Catholic presence in the community.