Kasugayama Primeval Forest (春日山原始林, Kasugaya-yama genshi-rin) is an area of 298.6 hectares (738 acres) of primeval forest in Nara, Japan, that is protected as a Special Natural Monument and which forms part of the UNESCO World Heritage Site Historic Monuments of Ancient Nara.

[2][3][4] Located in Nara Park to the east of the grounds of Kasuga Taisha and a Chinju no Mori,[5] hunting and logging on Mount Kasuga [ja] have been prohibited since 841.

[6] In 841, during the reign of Emperor Ninmyō, a prohibition was placed on hunting and logging on the sacred mountain.

[2]: 10  In 1922, Nara Park was designated a Place of Scenic Beauty under the 1919 Historical Sites, Places of Scenic Beauty, and Natural Monuments Preservation Law.

[7] Two years later, Kasugayama Primeval Forest was designated a Natural Monument, a designation upgraded in 1955 to that of Special Natural Monument, under the 1950 Law for the Protection of Cultural Properties.