An eastern spur of the Southern Alps, the Two Thumb Range runs in a predominantly north-south direction for approximately 45 kilometres (28 mi).

[1] Torlesse Composite Terrane rocks form the basement and range in age from the Jurassic near the Southern Alps to Permian in the east.

[41]: 1412 There is current and Quaternary displacement east of the Alpine Fault that has been ongoing for less than 5 million years that has resulted in uplift of the Two Thumb Range.

New Zealand's major north-to-south walking track, Te Araroa Trail, crosses the Rangitata River before following the valley of a tributary, Bush Stream, into the Two Thumb Range.

It crosses the range at Stag Saddle — the trail's highest point at 1,925 metres (6,316 ft) — immediately to the north of Mount Hope, before following the eastern shore of Lake Tekapo south.