In May 1960, a 38,762-hectare area of western Kanagawa Prefecture in the Tanzawa Mountains was designated for protection as the Tanzawa-Ōyama Prefectural Natural Park. The central portion of this area was further designated a quasi-national park on March 25, 1965.
Like all Quasi-National Parks in Japan, the park is managed by the local prefectural governments.[1]
^"List of Quasi-national Parks". Official Home Page of the Ministry of the Environment. Ministry of the Environment Government of Japan. 1994-03-31. Retrieved 2009-07-05.