Lost on the Old Grid: The History Behind Prospect Heights' Diagonal Buildings

In Prospect Heights, have you ever wondered why some buildings are built on a 45-degree angle from the rest of the grid?

The diagonal angles of the property lines are a remnant from a different street grid dating from the early 1800s. And building at a 45-degree angle is just what you do when you build a rectangular house on a diagonal plot.

In 1833, real estate speculators, including Charles Hoyt and James E. Underhill, began to sell lots in Prospect Heights measuring 25 feet by 100 feet that were part of a street plan laid out at about a 45-degree angle to the present street grid. This earlier grid was oriented towards what was then called Flatbush Turnpike or Old Flatbush Road.

Flatbush Turnpike was originally a Lenape Indian path that was widened by the Dutch settlers to make room for wagons. This road was to the east of the present day Flatbush Avenue and more of a meandering path that went up and over Prospect Hill, the second highest elevation in Brooklyn, next to the Brooklyn Museum.

This earlier street grid was also based on the farmland holdings by the early Dutch farmers and landholders Anthony Kerr, Andre Parmentier, and H.C. Beach. In this time, Prospect Heights was called Brooklyn’s 9^th ward and was primarily undeveloped farmlands, well into the 19^th century. 

David Ment and Mary S. Donovan in "The People of Brooklyn: A History of Two Neighborhoods," explain, “the mapping of city streets through the fields and woods of Dutch farmers did not mean that the streets would be opened immediately.”

It is unclear how many of the streets shown on the earlier grid were actually opened, but an application to the New York State Legislature in 1851 to close some of the streets, leads one to assume that at least some were occupied.

In 1839, despite the recent private sale of the land, the city of Brooklyn’s street grid was redrawn and extended through Prospect Heights. The first streets to open were Carlton Avenue and Dean Streets in 1846, both of which followed the new grid system. The remainder of the new streets opened through the 1850s including Flatbush Avenue in its new location, opening in 1852 and replacing the old Flatbush Road.

What became of these old streets? Close to Vanderbilt Avenue, the gracious brownstones have all but erased the old streets. However, in the area between Underhill and Washington Avenues the old grid still continues its legacy, producing some interesting angles, inconsistencies and a few buildings lost inside the old grid.

When the City redrew the grid, they kept the property lines from 1834 fairly intact in this small area. When the new streets ran across existing property lines at a different angle, parcels of land would be affected both by the old and new grid accounting for the several buildings, notably 323 Prospect Pl., being built along an angle or entire property lines going at a 45 degree angle. There is also a group of three buildings built on an angle and situated inside of the new grid with no outlet to the street save an alleyway and a doorway through another building.

In a city that is continually remaking it self, here is an example of some of Brooklyn’s oldest history, a grid oriented towards an Indian path and following Dutch farm property lines, continuing to make its mark on the landscape.