The neighborhood began as a summer resort in the 1920s; it was named after Wolfert Gerrritsen, a Walloon who built a house and mill on Gerritsen Creek in the first half of the 17th century.
Neighborhood description (http://www.house.gov/weiner/neighborhoods/hoods_gerritsenbeach.htm) from the website of the neighborhood's Congressman, Anthony Weiner
At its westernmost section, Brooklyn is closest to Staten Island at the Narrows, and the two are connected there by the Verrazano Narrows Bridge, where the Upper and Lower New York Bays meet.
The southeastern coast lies on island-dotted Jamaica Bay and is connected to Rockaway by the Marine Parkway-Gil Hodges Memorial Bridge, named after the Brooklyn Dodgers' first baseman who made his home in the borough.
The only municipal change seen was the secession of the eastern section of the Town of Flatbush as the Town of New Lots in 1852.