The island of Maui (; Hawaiian: [ˈmɐwwi]) is the second-largest island of the state of Hawaii at 727.2 square miles (1,883 km2), and the 17th-largest island in the United States. Maui is the largest of Maui County's four islands, which also include Molokaʻi, Lānaʻi, and unpopulated Kahoʻolawe. In 2020, Maui had a population of 168,307, the third-highest of the Hawaiian Islands, behind Oʻahu and Hawaiʻi Island. Kahului is the largest census-designated place (CDP) on the island, with a population of 28,219 as of 2020, and the island's commercial and financial hub. Wailuku is the seat of Maui County and is the third-largest CDP as of 2010. Other significant populated areas include Kīhei (including Wailea and Makena in the Kihei Town CDP, the island's second-most-populated CDP), Lāhainā (including Kāʻanapali and Kapalua in the Lāhainā Town CDP), and Upcountry Maui (including Makawao, Pukalani, and Kula).
Originally part of Maui Nui, Maui is dominated by two volcanic features: Haleakalā in the southeast, and the West Maui Mountains in the northwest. The two volcanos are connected by a small isthmus about six miles wide that gives the island its nickname, the Valley Isle.Maui has a significant tourism industry, with nearly three million visitors coming to the island in 2022. A 2023 report based on 2017 data concluded that nearly 40% of Maui County's economy was generated or induced by tourism. Popular tourist destinations include the resorts in the Kāʻanapali and Wailea areas; Hāna and the Hana Highway; Iao Valley; Haleakalā National Park; and locations for beach sports and activities.