Small township 19km north-west of Waipawa. Ongaonga was founded in 1872 by runholder H. H. Bridge. Like other runholders who founded towns, Bridge was paternalistic – he built a school and church and provided land for a recreation ground. Large pastoral runs in the district were subdivided into smaller farms between 1899 and 1905, which provided more business for the township and maintained its prosperity.

Meaning of place name
Native nettle. Other meanings are dog's tooth pattern used in carving, and snadfly. The settlement took its name from the stream.