== population density == 

 the article previously stated  The county is the seventh most densely populated in the nation, after the five boroughs of New York City (each of which is a unique county), Hudson County, and San Francisco County in California, which is made up entirely of the city of San Francisco.  Alternately, Essex County could be described as the most densely populated "suburban" American county, since the six counties denser than it are all mostly, if not entirely, made up of a city or several cities.  

 This isn't true.  First of all, seven counties are named there (the five boroughs plus two), not six.  Second, there are other counties with population densities greater than Essex (6298 per square mile), including Philadelphia, Pennsylvania (11234 per square mile; the city and county are legally the same); Suffolk County, Massachusetts (11788 per square mile, contains Boston).  I suspect that there are others, probably others containing major cities, but don't have the time to look for them right now.