Karnup is a semi-rural suburb situated in the southern part of the Perth metropolitan area, within the City of Rockingham in Western Australia. Located around 48 kilometers south of the Perth central business district, Karnup is bounded by other suburbs such as Secret Harbour, Baldivis, and Singleton. The area provides a transition between the more urbanized coastal suburbs and the rural hinterland, making it notable for its open spaces and bushland, as well as proximity to major transport corridors like the Kwinana Freeway and Mandurah Road.

Residential development in Karnup has historically been limited, with the suburb maintaining a mix of low-density housing, hobby farms, and larger rural properties. In recent years, there has been modest growth in newer residential estates, particularly in the north-western parts bordering the expanding urban fringe. Homes typically range from semi-rural lots to suburban residences, reflecting the area’s gradual evolution from predominantly agricultural land to a more diverse housing landscape.

Commercial development in Karnup is comparatively minimal, with local amenities consisting primarily of small shops, local service providers, and a few recreational and community facilities. Larger shopping, entertainment, and employment hubs are located in neighboring suburbs such as Secret Harbour or Warnbro. The demographic profile of Karnup tends to feature families seeking a rural lifestyle, retirees, and individuals involved in agriculture or equestrian activities, offering a peaceful living environment while still maintaining access to urban amenities nearby.