Batu Apoi Forest Reserve is located in Batu Apoi in the Temburong District of Brunei.

The Ulu Temburong National Park is located within the reserve.

[1] Its mountains reach altitudes of 1,000 metres (3,300 ft) around its southeastern borders.

The region features the shale lithology known as Setap Shale, and sometimes as Temburong Formation.

River channels, V-shaped valleys, and mixed Dipterocarp rainforest also characterize the forest reserve.