Crater Hill, Dormant volcano in Auckland Region, New Zealand

Crater Hill is a volcano in the Auckland volcanic field formed by an explosion crater about 600 metres wide, partly filled with water. Late in the eruption, lava welled up inside the crater into a lava lake; as the molten rock withdrew, the cooled basalt crust collapsed, leaving an island in the middle of the present lake and basalt remnants on the inner crater walls. Quarrying removed the small scoria cone and part of the tuff ring on the northeast side.

Crater Hill is one of the volcanoes of the Auckland volcanic field. Late in its eruption sequence, lava welled up inside the explosion crater and formed a lava lake, which cooled into a solid basalt crust. When the molten lava withdrew down the volcano's throat, the crust surface collapsed, leaving an island in the present lake and basalt around the inner crater walls. Quarrying later removed the small scoria cone and part of the tuff ring, and the Southwestern Motorway was cut through the northeast rim.

Crater Hill is one of the volcanic features the Tāmaki Māori call Nga Tapuwae a Mataoho, "The Sacred Footprints of Mataoho", after the deity in their myths who helped create them. The name links the hill with Māngere Lagoon, Waitomokia, Kohuora, Pukaki Lagoon and Robertson Hill.

The hill is accessible to visitors, and two historic lava caves named Selfs and Underground Press can be explored on the southern side beneath the basalt crust. Sturdy footwear and cautious movement are recommended, as the terrain is uneven and caves have limited lighting.

The island in the lake is the collapsed surface of a lava lake: when the molten lava withdrew down the volcano's throat, the solid basalt crust caved in. Basalt left on the crater's inner walls still marks the former lava-lake level.