When I tell people I live in Southwest, most people ask: "Where is that? I've never been there before." I then tell them: "Have you been to the National Air & Space Museum or the Jefferson Memorial?" They usually say: "Yes." Then I say: "Then you've been to Southwest." "Oh, I didn't know that was in Southwest." they normally respond.
Southwest is the smallest quadrant of the District of Columbia, following the axis of the U.S. Capitol Building, but it always wasn't so small. When the capital of the United States was originally formed in the late 18th century by combining territories from the Commonwealth of Virginia and the State of Maryland, Arlington County and the City of Alexandria formed part of the District of Columbia, with all of Alexandria and part of Arlington located in the Southwest quadrant of the newly created capital. However, in the mid part of the 19th century, the District ceded Arlington and Alexandria back to Virginia, which greatly reduced the size of Southwest to what it is today.
The main neighborhoods that comprise the Southwest quadrant include the National Mall, Federal Center SW, Southwest Waterfront, Buzzard Point, and Bellevue, each with their own distinct character.