The Principality of Hutt River, previously known as the Hutt River Province, is the oldest micronation in Australia. The principality claims to be an independent sovereign state. It is unrecognized except by other micronations, but got de facto legal status on 21 April 1972.

The principality is located 517 kilometres (321 mi) north of Perth, near the town of Northampton.

The principality was founded on 21 April 1970 by Leonard George Casley when he and his friends proclaimed their secession from the state of Western Australia.