Castor Bay is a suburb which lies within the Territorial Authority of Auckland, one of 269 residential suburbs which form the wider region. Castor Bay is the 99th largest suburb of Auckland in terms of the total number of residential housing stock. Castor Bay provides a range of housing stock, with the earliest residential housing recorded in the area constructed between 1910 - 1919. The majority of the residential housing stock in the locality was constructed between 1970 - 1979. Residential housing stock in Castor Bay is made up of approximately 97% residential housing and 3% residential investment housing properties.