At the turn of the 20th century, the Lower East Side was widely reported to be the most densely populated place on earth.
When the New York City Tenement House Department undertook a survey of the city’s tenement housing stock in 1903, they found the Lower East Side’s Tenth Ward to have a population of 69,944, or approximately 665 people per acre.
With a total population of 2,223 people, the 2.04 acre block bounded by Orchard, Broome, Delancey and Allen Streets was the most densely populated in the ward. Situated in the middle of this block, 97 Orchard Street’s population peaked at 111 residents in 1903, up from 72 people in 1870.
According to Andrew Dolkart’s new book, Biography of a Tenement House in New York City: An Architectural History of 97 Orchard Street, several factors help explain the Lower East Side’s extraordinary population density at the turn of the 20th century. Large numbers of eastern European Jewish and Italian immigrants settled in the neighborhood during this period in search of affordable housing and ethnic and religious community.
On the Lower East Side, the destruction of tenements to make room for schools and parks displaced large numbers of people, many of whom relocated to already overcrowded tenements on nearby blocks in the neighborhood.

This photo gives a glimpse of the crowded streets of the Lower East Side. Dating from the late 19th century, the photo depicts the corner of Division street and East Broadway, just a few blocks away from the tenement at 97 Orchard Street.
(Photo courtesy of the Library of Congress.)