Mount D'Archiac is the highest peak in the Two Thumb Range which is a subrange of the Southern Alps.

It is situated 180 kilometres (112 mi) west of the city of Christchurch and is set on the eastern boundary of Aoraki / Mount Cook National Park in the Canterbury Region of South Island.

The first ascent of the summit was made in March 1910 by Jim Dennistoun, Laurence Earle, and Jack Clarke via the East Ridge and Forbes Glacier.

[2] The mountain was named by Julius von Haast to honour Vicomte d'Archiac (1802–1868), a French geologist and professor of palaeontology at the Paris Museum of Natural History.

This climate supports the Dennistoun, Trident, FitzGerald, Separation, and South Forbes glaciers on this mountain's slopes.