Mount Harper is located 120 kilometres (75 mi) northwest of Christchurch on the boundary of Arthur's Pass National Park in the South Island.

Topographic relief is significant as the summit rises 940 metres (3,084 feet) above the White River in one kilometre.

[2] The mountain's toponym was applied in 1926 to honour Arthur Paul Harper (1865–1955), a New Zealand lawyer, mountaineer, explorer, businessman, conservationist, and for many years president of the New Zealand Alpine Club as a founding member.

[6] Prevailing westerly winds blow moist air from the Tasman Sea onto the mountains, where the air is forced upwards by the mountains (orographic lift), causing moisture to drop in the form of rain or snow.

The months of December through February offer the most favourable weather for viewing or climbing this peak.