The suburbanization of Montgomery County began in the late 19th and early 20th century along the Metropolitan Branch of the B&O railroad and the streetcar lines that extended into the County from the District of Columbia.

During the automobile-oriented 20th Century, suburban growth expanded into all areas of the County except the agricultural preserve in the northeastern and northwestern areas of the upper County.

The first two decades of 21st Century have seen a shift away from low density residential and commercial development to a smart growth emphasis on high density, pedestrian friendly, transit oriented development along the Metro Red Line routes and the I-270 corridor.