It's a small state adjacent to two great port districts, and to two very large cities. That created opportunities for manufacturing, for warehousing and supply of New York City and Philadelphia, building dense settlements like Trenton, Hoboken, Jersey City, and Newark. Easy access to the office jobs of Manhattan (and to a lesser extent, Center City Philadelphia) led in the 20th century to the creation of "bedroom" suburbs that are less dense than industrial cities but much more dense than farmland.