The island is shaped approximately like a crescent, with its concave edge facing the south. The land area is approximately 83 km² (32 sq. mi.). The center of the island is a high plateau, deeply indented in places by narrow river valleys. The highest peak, Hitikau reaches an elevation of 884 metres (2,900 ft). Much of the island's native plant cover, which outside the valleys consists primarily of dryland scrub, has been devastated by herds of feral goats and horses, which are estimated to number upwards of 3,000.
Ua Huka is a shield volcano that was emplaced between 2.2 and 2.4 million years ago. It is thought to have formed by a center of upwelling magma called the Marquesas hotspot. The island is served by Ua Huka Airport.
The administrative centre of the commune is the settlement of Vaipaee, on the southern side of the island.
Although the primary economic activity remains the production of copra, Ua Huka has rich resources for tourism, including restorations of various archæological sites, museums displaying the former glory of Marquesan civilization, and the preservation of the island's unique flora. Among the archæological remains at sites such as Tehavea and Meiaute are ancient petroglyphs and thousands of bird bones. The Pupuakeiha Arboretum consists of 42 acres (17 ha) planted with over 300 species of trees. It is hoped that one day this wealth of species will be able to be used to reforest the island. On the western end of the island are found a number of sea-caves.