Port Underwood is a suburb which lies within the Territorial Authority of Marlborough, one of 36 residential suburbs which form the wider region. Port Underwood is the 25th largest suburb of Marlborough in terms of the total number of residential housing stock. Port Underwood provides a range of housing stock, with the earliest residential housing recorded in the area constructed between 1890 - 1899. The majority of the residential housing stock in the locality was constructed between 2000 - 2009. Residential housing stock in Port Underwood is made up of approximately 77% residential housing , 1% residential investment housing and 22% lifestyle properties.