It’s hard to characterize the size or importance of Gaithersburg. The city limits are actually fairly small. Since Maryland incorporation laws favor counties Baltimore is the only city significantly larger than 50,000. If you include the unincorporated areas that essentially serve as Gaithersburg suburbs (Montgomery Village, North Potomac, etc.) though, the population expands to about 150,000, and if you include everyone with a Gaithersburg address it balloons to include everything from Damascus to the Potomac River and is probably well over 200,000.
Within the actual city there are three districts noteworthy for their urbanity: Washingtonian, Greater Kentlands and Old Town: Washingtonian is functionally downtown Gaithersburg. It’s home to the most intense uses, tallest buildings and best entertainment. The immediate lakefront is one of the most enjoyable and vital places outside the Beltway. Unfortunately quality urbanism doesn’t extend off the lakefront much, and within a few blocks the neighborhood can be characterized by suburban (though admittedly statistically dense) apartment blocks.
Greater Kentlands serves as a sub-center for the city’s West Side. The neighborhood is easily the most urban significantly west of I-270 and Market Square is quickly becoming the place to be for family entertainment and restaurants. It’s more urban than one would expect from greenfield new urbanism, but can also feel a bit too “cutesy” for people familiar with authentic urbanity.
Old Town basically does for the East Side what Kentlands does for the West Side. While Old Town was at one time a truly functional downtown it has lost its place in recent decades. Determined to protect the small-town character of the neighborhood city leaders inserted historical protections and strict building intensity limits such that as the city grew the tiny historic core ceased to function as the heart of town and instead became a quaint little village. Although the late 1990s saw some attempts at revitalization and a new highway exit promises to bring some life to the area, potential seems limited for Old Town. Unfortunately it’s more nostalgic than important.