Rolleston is the seat and largest town in the Selwyn District, in the Canterbury region of New Zealand's South Island. It is located on the Canterbury Plains 22 kilometres (14 mi) south-west of Christchurch, and is part of the wider Christchurch metropolitan area. The town has a population of 29,600, making it New Zealand's 23rd-largest urban area and the second-largest in Canterbury.

Selwyn District is a predominantly rural district in central Canterbury, on the east coast of New Zealand's South Island. It is named after the Selwyn River / Waikirikiri, which is in turn named after Bishop George Selwyn, the first Anglican bishop of New Zealand who, in 1843 and 1844, travelled the length of the country by horse, foot, boat and canoe, leaving in his wake a sprinkling of locations that now bear his name.