America's Riches...To determine America’s richest counties, Forbes looked at median annual household income estimates from 2006 to 2010 in each county in the nation, provided by the U.S. Census’ American Community Survey. The estimates are in 2010 inflation-adjusted U.S. dollars.
With 285,000 residents, this county south of Denver has boomed over the last decade, luring young professionals with luxury homes, planned communities and 71 square miles of permanently protected land.
Even though it’s far from Washington, Los Alamos County’s wealth is still largely the result of federal government spending. The biggest employer in the richest county in the Western United States is the Los Alamos National Laboratory.
With 1.1 million residents, Fairfax is Virginia’s most populous county. The federal government fuels the economy—Fairfax is home to the CIA and National Counterterrorism Center and companies with strong government ties like Freddie Mac.
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.