The river rises in the low hills to the south of Silverdale and flows into Karepiro Bay on the Hauraki Gulf / Tīkapa Moana.

The river is extremely tidal with only a narrow channel being navigable by small craft at low tide.

The sand banks (above high tide mark) in Karepiro Bay are Dotterel breeding areas, protected by DOC (Department of Conservation).

The northern shore of the Ōkura River was traditionally known as Otaimaro, and was an extensive Māori settlement.

Their house, the Dacre Cottage, was built circa 1855 from locally made bricks.