The most populous cities in area code 240 are: Frederick, Mount Rainier, Rockville, Laurel, and Silver Spring.
Other cities in the 240 area code include: Bethesda, Hagerstown, Gaithersburg, Hyattsville, Cabin John, Waldorf, Sandy Spring, Beltsville, Capitol Heights, Cumberland, Chevy Chase, Leonardtown, Columbia, Glenn Dale, College Park, Oxon Hill, Upper Marlboro, Montgomery Village, Kensington, Damascus, Hughesville, Brandywine, Clinton, La Plata, Myersville, Great Mills, Mechanicsville, Ridge, Poolesville, Oakland, Indian Head, Newburg, Westernport, Nanjemoy, Mount Airy, Clarksville, Hancock, Adamstown, Emmitsburg, Middletown, Clear Spring, Thurmont, Grantsville, Smithsburg, Cascade, Williamsport, Greenbelt, Lexington Park, Friendship, Bittinger, Kitzmiller, Brunswick, Keedysville, Lonaconing, Frostburg, Odenton, Ijamsville, Walkersville, District Heights, Temple Hills, New Market, Baltimore, Tall Timbers, Ashton, Crofton, Friendsville, Flintstone, Mount Savage, and Callaway.
Frederick is a city and the county seat of Frederick County in the U.S. state of Maryland. It is part of the Baltimore–Washington Metropolitan Area. Frederick has been an important crossroads community since it was located in colonial times at the intersection of an important north–south Indian trail, and east–west routes to the Chesapeake Bay both at Baltimore and what became Washington, D.C. and across the Appalachian mountains to the Ohio River watershed. It is a part of the Washington-Arlington-Alexandria, DC-VA-MD-WV Metropolitan Statistical Area, which is part of a greater Washington-Baltimore-Arlington, DC-MD-VA-WV-PA Combined Statistical Area. The city's population was 65,239 people at the 2010 United States Census, making it the second-largest incorporated city in Maryland, behind Baltimore.Frederick is home to Frederick Municipal Airport (IATA : FDK), which primarily accommodates general aviation traffic, and to the county's largest employer U.S. Army's Fort Detrick bioscience/communications research installation.
Mount Rainier / r eɪ ˈ n ɪər / is a city in Prince George's County, Maryland, United States. The population was 8,080 at the 2010 census. Bordering Washington, D.C., Mount Rainier got its start as a streetcar suburb. (See Streetcars in Washington, D.C.) According to local tradition, surveyors from the Pacific Northwest named the town, giving the streets names such as " Shasta " and " Cascade ". Historic U.S. 1 runs through the center of the town and serves as the main street and central business district.
Rockville is a city located in the central region of Montgomery County, Maryland. It is the county seat and is a major incorporated city of Montgomery County and forms part of the Baltimore–Washington metropolitan area. The 2010 census tabulated Rockville's population at 61,209, making it the third largest incorporated city in Maryland, behind Baltimore and Frederick. Rockville is the largest incorporated city in Montgomery County, Maryland, although the nearby census-designated place of Germantown is more populous. Rockville, along with neighboring Gaithersburg and Bethesda, is at the core of the Interstate 270 Technology Corridor which is home to numerous software and biotechnology companies as well as several federal government institutions. The city also has several upscale regional shopping centers and is one of the major retail hubs in Montgomery County.
The 240 area code lies within the Eastern Daylight Time Zone (or EDT). The current time in Eastern Daylight Time is 12:22 AM on May 04, 2024.