The Rise and Fall of Manhattan’s Density

Photo of a tenement room in 1902 taken during an inspection by the new york city tenement house department
Photo of a tenement room in 1902 taken during an inspection by the New York City Tenement House Department © NYPL

In 1951, economist Colin Clark published the seminal paper “Urban Population Densities” in which he observed that urban population density tends to decline the further one gets from city centers. This made sense: land is cheaper outside the city center, so it doesn’t have to be occupied quite as compactly. In the years since, several more studies have looked at changes in an urban area’s average density over time. But few have looked at changes in density across both time and space within a particular urban area. So NYU professor Shlomo Angel, a senior research scholar at NYU Stern’s Urbanization Project, set out to do just that for Manhattan between 1800 and 2010.

It is a story of a century-long intensification of people, jobs, and houses on the island, followed by an equally long — and equally dramatic — decongestion. In the second half of the 19th century, Manhattan’s population growth far outstripped the rate of new home construction. In 1910, Manhattan reached a peak population of 2.2 million, from which it has never since rebounded, even after modest growth in the past three decades. Angel’s research found that today, Manhattan’s population density is down a surprising 40% from 1910. []