Sister cities of Montgomery County, Maryland

Montgomery County is a county in the U.S. state of Maryland, situated just to the north of Washington, D.C., and southwest of the city of Baltimore. It is one of the most affluent counties in the United States, and has the highest percentage (29.2%) of residents over 25 years of age who hold post-graduate degrees. The county seat and largest municipality is Rockville; although the census-designated place of Germantown is more populous. As of 2010 the population was 971,777 and the county reached an estimated population of over 1 million residents with the 2012 U.S. Census Bureau update which shows that 1,004,709 residents now live in the county. Most of the county's residents live in unincorporated locales, the most populous of which are Silver Spring, Germantown and Bethesda, though the incorporated cities of Rockville and Gaithersburg are also large population centers. It is a part of both the Washington Metropolitan Area and the Baltimore-Washington Metropolitan Area.

As of 2008, Montgomery County is the second richest county in terms of per capita income in the state of Maryland. In 2011, it was ranked by Forbes as the 10th richest in the United States, with a median household income of $92,213.