The Iolani Palace In Honolulu, Oahu, Hawaii, USA. Iolani Palace, the only royal palace in the USA; downtown historic district, Honolulu, Oahu, Hawaii. The ʻIolani Palace was the royal residence of the rulers of the Kingdom of Hawaii beginning with Kamehameha III under the Kamehameha Dynasty (1845) and ending with Queen Liliʻuokalani (1893) under the Kalākaua Dynasty, founded by her brother, King David Kalākaua. It is located in the capitol district of downtown Honolulu in the U.S. state of Hawaiʻi. It is now a National Historic Landmark listed on the National Register of Historic Places. Kamehameha III, IV, V, and Lunalilo had their official royal residences in this location as well.