The Selwyn River flows through the Selwyn District of Canterbury in the South Island of New Zealand.

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.