Ash Hill, Volcanic formation in Wiri, Auckland, New Zealand.

Ash Hill is a low tuff cone in Wiri, South Auckland, with an explosion crater about 150 metres wide. Its summit once stood roughly 30 metres above sea level, only some 8 metres above the surrounding land. The cone has been largely quarried away and is now covered by industrial development.

Ash Hill is a low tuff cone of the Auckland volcanic field, radiocarbon dated to 31,800 ±159 calendar years BP, an age close to that of nearby Wiri Mountain (Matukutururu). The cone and its 150 m explosion crater have been largely quarried away and built over by industry in Wiri.

The name was given by Earnest J. Searle after nearby Ash Road, which is named for ash trees, not volcanic ash. The cone itself has been largely quarried away and is covered by industrial buildings, so the name now survives mainly in the road and the industrial address.

The crater and cone are largely quarried away and built over by industry in Wiri, so there is no summit track or marked viewpoint. The site lies near Ash Road, off Wiri Station Road; treat it as a roadside feature seen from public streets rather than a destination to walk into.

Ash Hill's name comes from Ash Road, which was named after ash trees, not volcanic ash. Its radiocarbon age of 31,800 ±159 years is close to that of nearby Wiri Mountain (Matukutururu), and the cone once stood about 8 metres above the surrounding land.