In 1811, the Commissioner’s Plan established Manhattan’s street grid from Houston Street (then the city’s northern edge) on up. But bombastic as this act of speculative urban planning may have been, it only went so far—155th Street, to be exact. By the 1860s, planning for the urbanization of Manhattan’s northernmost reaches began in earnest under Andrew Haswell Green’s Central Park Commission. Green extended the numbered grid, but also adapted the streets to the area’s dramatic topography, creating a unique area within Manhattan’s urban fabric, full of charming side streets (quaintly designated as “terraces”), bucolic hillside parks, and stunning vistas. During OHNY Weekend, explore this unique area to learn about a critical moment in the city’s historical development. All of these sites are Open Access during the times and dates indicated below, and do not require reservations.



Morris-Jumel Mansion

Saturday, October 17: 10:00 am – 6:00 pm; Sunday, October 18: 10:00 am – 2:00 pm.

This stately structure has the distinction of being Manhattan’s oldest residence. Built by British military officer Roger Morris in 1765, the mansion served as the headquarters for both sides during the American Revolutionary War. Today, the mansion contains one of the few landmark interiors in the five boroughs. Visit during OHNY Weekend to see how wealthy landowners like Stephen Jumel—who bought and remodeled the mansion in 1810—lived in this area at a time before the city had made its way up into the Heights. Tours will be offered on both days.


M-NYPL Washington Heights Library_credit Vanni Archive

NYPL Washington Heights Library

Saturday, October 17: 10:30 am4:30 pm.

The Jumel heirs broke up the 115-acre estate surrounding the Morris-Jumel Mansion in 1882, as the re-mapped Heights began to develop in earnest. The area became a fine residential district, (today known as the Jumel Terrace Historic District), and in 1914 a Carnegie Library was built on the edge of the old estate. On the Saturday of OHNY Weekend, tour this Carrère & Hastings-designed structure with Dattner Architects principal Joseph Coppola to learn about the library’s renovation, completed last year just in time to mark the building’s 100th “birthday.”



Hispanic Society of North America

Saturday & Sunday, October 17-18: 12:00 pm4:00 pm.

Named for legendary American naturalist John James Audubon (and sited on a piece of what was once Audubon’s rural estate), historic Audubon Terrace is a monumental, museum-lined plaza tucked into the Manhattan grid between 155th and 156th Streets. Philanthropist Archer Milton Huntington created this impressive City Beautiful-style complex at the height of the Heights’ development—a time when it seemed like the city’s cultural center of gravity might very well be shifting uptown. Today, the complex is anchored by the Hispanic Society of America, a stunning museum and library that will offer free tours on both days of OHNY Weekend.


Randel Map

Manhattan Borough President’s Map Display

Saturday, October 17: 10:00 am4:00 pm.

Before or after you head up to the Heights, don’t miss a very special display of the Randel Farm Maps at the Manhattan Municipal Building downtown, organized and hosted by Manhattan Borough President Gale Brewer. Never before publicly exhibited in full, all 92 panels of the maps—the first that plotted the 1811 Commissioner’s Plan—will be on display during the Saturday of OHNY Weekend. Get feel for how upper Manhattan looked in the days before the grid, when country estates and forested hillsides dominated the local landscape.