Population Density of Cities

http://www.citymayors.com/statistics/largest-cities-area-125.html

Take even the largest cities. NYC at 18M and 7000 sq km. That is still only 6 people per acre.

7000 sq km is 1.7M acres. So about 10 people per acre. By the same density, Factor e Farm would need to have only 300 people to achieve the same density. And the question is -