Republic of Castonia.
Banner of Castonia

"In God we trust"
Portland Island
Capital city Caston
Largest city Beihgh
Official language(s) English
Official religion(s) Roman Catholic
Demonym Castonian
Government Nationalist Single-party state
- President Thomas Nelson
- Prime Minister Sam Baker
Legislature The Tagerad
Established 24 October 2013
Population 8
Currency Gulder (#)
National animal Emu

Castonia, officially the Republic of Castonia, is a government in exile which claims to be the legitimate governing body of Portland Island,an island in the Southern Gulf Islands of the South Coast of British Columbia, Canada. It claims to be an independent sovereign state but has received no recognition from world governments.

The was given to Princess Margaret in 1958 to commemorate her visit to the province. Princess Margaret returned the island to British Columbia in 1967, after which point it became a Provincial Park. Today, Princess Margaret (Portland Island) is a part of Gulf Islands National Park Reserve,