The Whanganui River winds its way from the mountains to Wanganui City by the Tasman Sea. It flows through countless hills and valleys. Lowland forest surrounds the river in its middle and lower reaches, forming the heart of the Whanganui National Park.
The early Maori cultivated the sheltered terraces and built elaborate eel weirs along river channels where eels and lamprey were trapped on their, migration up river. Every bend of the river had a kaitiaki (guardian) which controlled the mauri (life force) of that place.
The mana (prestige) of a settlement depended upon the way in which food supplies and living areas were looked after for the benefit of the hapu/tribe and visitors.
The first major European influence arrived with missionaries in the 1840s. In 1891 a regular river-boat service began carrying passengers, mail and freight to the European settlers on the river between Taumarunui and Pipiriki and a thriving tourist trade soon began between Mt Ruapehu and Wanganui. The main riverboat trade ceased in the 1920s, due to better roads, a main trunk railway and other tourist attractions, although river-boats were still operating in the late 1950s.
The land surrounding the river is formed of soft sandstone and mudstone (papa) from the ocean-bed, it has been eroded by water to form sharp ridges, deep gorges, sheer papa cliffs and waterfalls. Over this land has grown a broadleaf-podocarp forest of rata, rewarewa, rimu, tawa, kamahi and kowhai with breech dominant on ridge tops. Tree ferns and plants that cling to the steep river banks are very distinctive. Bird species such as kereru (native pigeon), tiwaiwaka (fantail), tui, toutouwai (robin), riroriro (grey warbler), miromiro (tomtit) and the bellbird are often seen and heard.
The call of the brown kiwi can often be heard at night.
Long tailed bats are often seen high above the trees at dusk in some areas of the park.