The Manawatu-Whanganui Region, or Manawatu-Wanganui Region, is named for Whanganui and Manawatu River.
The alternative spelling if the name are just one aspect of the Maori cultural revival that is centred in this part of New Zealand.
The Whanganui (or Wanganui) River is, unlike most New Zealand rivers is navigable from the sea to its upper reaches. For many years the river was the only transport route to the inland communities and farms.
The city of Wanganui lies at the mouth of the river.
The Manawatu River is powerful enough to cut a gorge through the main mountain range that separtates the eastern and western coasts of the North Island, the Manawatu River drains both sides of the mountain ranges.