A central East-West mountain range dominates the geography of New Guinea, over 1600 km in total length. The western section is around 600 km long and 100 km across. Steep mountains 3000 to 4000 m and up to 5000 m high along the range ensure a steady supply of rain from the tropical atmosphere. The tree line is around 4000 m elevation and the tallest peaks are snowbound year round.
Both North and West of the central ranges the land remains mountainous mostly 1000 to 2000 m high covered by thick rain forest and a warm humid year round climate. The third major habitat feature is the southeast lowlands with extensive wetlands stretching for hundreds of kilometers.
Mamberamo River sometimes referred to the “Amazon of Papua” is the province’s largest river, which winds through the northern part of the province. The result is a large area of lakes and rivers known as the Lakes Plains region. The famous Baliem Valley, home of the Dani people is a tableland 1600 m above sea level in the midst of the central mountain range; Jaya Peak, sometimes known by its former Dutch name Carstensz Pyramid, is a mist covered limestone mountain peak 5030 m above sea level.