Marlboro Township has a land are of 30.31 square miles (87.5 km2) and is located in western Monmouth County, on the border of Middlesex County. Today, Marlboro is one of the fastest growing municipalities in the county, accommodating a range of land uses including offices, retail and service enterprises, light industrial, and, of course, housing. Marlboro's housing stock includes estate homes scattered on large lots, post-war and recent single family residential subdivisions, and higher density town homes.