This mixed-use national park is home to small swatches of primary rainforest, but also includes plantations such as the Nirmala Tea Estate. The park's best feature is the rich montane forest in the highland regions around Gunung Halimun (1929m), its tallest peak. The scenery is ravishing and there's a lot of wildlife (though most of it is hard to see), including langurs and gibbons as well as profuse bird life. Several happy days could be spent hiking here.
The most popular walk is a half-day hike taking in three waterfalls.
ArusLiar Adventure is a recommended local operator running hiking trips in the park and white-water rafting in the peripheral areas. Otherwise, speak to the staff at the tourist office in Bogor about setting up a trip.
The usual access (you need your own transport) is through Cibadak on the Bogor–Pelabuhan Ratu road, from where you turn off to Cikadang and then on to the Nirmala Tea Estate. Rainfall in the park is between 4000mm and 6000mm per year. Most of this falls from October to May, when a visit is more or less out of the question. There is a helpful park office on the eastern edge of the village of Kabandungan.