The island is across at its widest point and covers an area of . The highest peak is Mont Orohena (Mou'a 'Orohena) (). Mount Roonui, or Mount Ronui (Mou'a Rōnui), in the southeast rises to . The island consists of two roughly round portions centered on volcanic mountains and connected by a short isthmus named after the small town of Taravao, which is situated there.