The Oostvaardersplassen (Dutch pronunciation: [oːstˈfaːrdərsˌplɑsə(n)]) is a nature reserve in the Netherlands, which is managed by the State Forestry Service. Covering about 56 square kilometres (22 sq mi), it is noted as an experiment of rewilding. It is in a polder which was created in 1968; by 1989, its ecological interest had resulted in its being declared a Ramsar wetland. It became part of Nieuw Land National Park when it was created in 2018. The governing body is the Province of Flevoland and the management lies with Staatsbosbeheer.