Perth is divided into 30 local government areas and over 250 suburbs, with the metropolitan boundaries stretching from Two Rocks in the north to Singleton in the south, and east inland to The Lakes. Outside of the central business district, important urban centres within the metropolitan area include Armadale, Fremantle, Joondalup, Midland and Rockingham. Most of those were originally established as separate settlements and retained a distinct identity after being subsumed into the wider metropolitan area. Mandurah, Western Australia's second-largest city, forms a conurbation with Perth along the coast, though for most purposes it is still considered a separate city.