In 1900, tenement blocks on the Lower East Side were the densest in the world with over 1,000 people per acre. Up to ten people could share a single room. Overcrowded conditions and high lot coverage resulted in extraordinary density. Knickerbocker Village, with 12 stories, meant to modernize Lower East Side tenements, housed 800 people per acre in 1934, with courtyards leaving 53% open space.
Today, reduced occupancy of units in Lower East Side tenements creates a density of around 400 people per acre. Knickerbocker Village, with 684 people per acre, is today substantially more dense than the typical 4-story tenement block.