Median annual household income
The nation’s richest county used to be a sleepy rural farmland with some 300 dairy farms, but now only one dairy remains. It has benefitted from its close proximity to Washington D.C. and the boom in federal government spending. More From Forbes
: America’s Most Affluent Neighborhoods The World’s Richest Countries The World’s Billionaires The opinions expressed are solely those of the author and do not necessarily reflect the views of Comcast.