Gaithersburg), officially the City of Gaithersburg, is a city in Montgomery County, Maryland. 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, D.C., 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".