The name
whāngā nui means big bay or big harbour.
(whanga = bay), (nui = big)

The first name of the European settlement was Petre (pronounced Peter), after Lord Petre, an important officer of the New Zealand Company. It was changed to Wanganui in 1852.

While Wanganui is the official spelling of the district, the word wanga has no meaning in Maori. In accord with the wishes of local iwi, the river’s name reverted to Whanganui in 1991.

The region’s name is sometimes spelt “Whanganui”, but the District has kept the spelling “Wanganui”. (see Wanganui or Whanganui for more details.)