Haven Island is an island in the Ocean of Dreams.
In PRPG2
It is inhabited by a violently isolationist colony of ponies founded in the Dark Age; the principle settlement is Martingale's Haven.
In PRPG3
The island has opened up somewhat and is marginally better known now due to census efforts, although the population is generally still very much isolationist. They have resisted all modern influences from Harmonia and greater Yore, even basic emergency and healthcare services. Crime rates on the island are unknown for lack of reporting; indeed, it is unclear whether there even are laws in a formal sense. The island's form of governance is likewise unknown.
Despite all this, the islanders do occasionally contact the mainland with limited trade requests. The few outsiders who have visited the island since the end of the Dark Age and the return of the seas have not been violently repelled, but do report being treated coldly, especially if visiting uninvited. Officially, Harmonia strongly discourages unrequested visits, although they are not technically illegal.