- Hilo is a city located on the east coast of the island of Hawaii in the state of Hawaii, USA. It is the largest city on the island and the fourth-largest city in the state, with a population of around 45,000 people. Hilo is known for its beautiful natural scenery, including lush rainforests, waterfalls, and the nearby Mauna Loa volcano. The city is also home to the University of Hawaii at Hilo and is a popular tourist destination, with attractions such as the Hilo Farmers Market, the Pacific Tsunami Museum, and the Imiloa Astronomy Center. The tropical climate of Hilo makes it a great place for outdoor activities such as hiking, surfing, and snorkeling.