The Lower East Side in New York City is the section of southeast Manhattan (40°43′N 73°59′W). It was a popular place for immigrants to settle during the during the nineteenth and early twentieth centuries. (Columbia Gazetteer of the World, http://www.columbiagazetteer.org/main/ViewPlace/0/81511). The map below shows the population density by block in 1910.
Source: Map and key from Eric Homberger, The Historical Atlas of New York City: A Visual Celebration of 400 Years of New York City’s History, Revised ed. (New York: Henry Holt and Company, 2005), 132.