left|thumb|360px|Pheasant Island from the International Bridge over the Bidasoa River. On the left Hendaye, France/" class="wiki">Irún, Spain; on the right Hendaye, FrancePheasant Island is a river island located in the River Bidasoa. The island is a condominium, under joint sovereignty of Spain and France, and so administered by Irún (in Guipúzcoa, Spain) and Hendaye (in the Pyrénées-Atlantiques, France), which are in charge of the island during alternating periods of six months. It has a surface of 6,820 m² and has been artificially protected from the currents of the river.

The island is called Isla de los Faisanes in Spanish, Île des Faisans, Île de l’hôpital or Île de la Conférence in French and Konpantzia in Basque.

The most important historical event that took place on the island was the signing of the Treaty of the Pyrenees after a series of 24 conferences between Luis de Haro and Cardinal Mazarin in 1659 to end the Thirty Years' War. A monolith in the centre of the island was raised to commemorate this event.