[6] Ōhau was opened as a flag station by the Wellington and Manawatu Railway Company on Monday 2 August 1886, when trains started to run between Longburn and Ōtaki.

In 1912 it was planned that down express engines would water at Ōhau and in 1913 a new well was sunk and a shed was shifted from Ōtaki for use as a pump house.

By 1923 AB class engines were able to fill up at Ōhau, but in 1935 vat and windmill were replaced by a small tank.

A goods shed, high-level loading bank, low-level loading bank and a lean-to type station building with waiting room and ticket office remained, but the station and goods shed were demolished later that year.

[5] Just south of the station the NIMT crosses the Ōhau River on a 6-span steel girder bridge, supported on concrete piers.