Loudoun County was founded in 1757 and is located in the Primary Metropolitan Statistical Area, which encompasses Washington, DC. Arlington, and Alexandria as well as other neighboring counties and cities located in the surrounding states of West Virginia and Maryland. Loudoun County is comprised of 520 square miles of land, a civilian work force of 211,626, seven universities and colleges, nine community centers, eight public libraries, and 90 public schools. The population in Loudoun County continues to grow at a rapid rate. According to the Census Bureau in 2010, the population in Loudoun was 312,311. Current estimate of Loudoun County’s population is 402,561, a growth of approximately 22%. The median household income in Loudoun County has increased recently as well from over $119,000 in 2011 to $134,464 in 2016. This increase ranked Loudoun County first in the United States of America in median household income.