Gaithersburg ( pronunciation ), officially the City of Gaithersburg, is a city in Montgomery County, Maryland, United States. At the time of the 2010 U.S. Census, Gaithersburg had a population of 59,933, making it the fourth-largest incorporated city in the state, behind Baltimore, Frederick, and Rockville. Gaithersburg is located to the northwest of Washington, and is considered a suburb and a primary city within the Washington–Arlington–Alexandria, DC–VA–MD–WV Metropolitan Statistical Area. Gaithersburg was incorporated as a town in 1878 and as a city in 1968.
Gaithersburg is divided into east and west sections, separated by Interstate 270. The eastern section of the city is older and is the original portion of the town before more recent growth. Landmarks and buildings from that time can still be seen in many places but especially in the historic central business district of Gaithersburg called "Olde Towne". The east side also includes Lakeforest Mall, City Hall, and the Montgomery County Fair grounds, and Bohrer Park (a well-known joint community recreation center and outdoor water park for kids and families). The west side of the city has many wealthier neighborhoods that were designed with smart growth techniques and embrace New Urbanism. These include the award-winning Kentlands community, the Lakelands community, and the Washingtonian Center (better known as Rio), a popular shopping/business district.