 Not all suburbs are necessarily covered by any of the following informal regional categories.The regions are Canterbury-Bankstown, the Eastern Suburbs, the Forest District, Greater Western Sydney, the Hills District, the Inner West, the Macarthur region, the Northern Beaches, the Northern Suburbs, the North Shore, Southern Sydney, South-western Sydney, the St George district, the Sutherland Shire and Western Sydney.The Blue Mountains are at times considered to be part of Sydney's metropolitan area.