Manhattan has about 1.6 million residents sharing just under 23 square miles of land. Meanwhile, 669 square mile Loving County, TX has just 86 residents.
We wanted to explore the wide dispersion in the population density of the US's 3,142 counties.
The 244 densest US counties are shown in dark purple in the map below. According to the Census Bureau's population estimates for 2014 and their tabulations of the land area of each county, 50.1% of the US population lives in those counties:
Business Insider/Andy Kiersz, data from US Census Bureau