Honolulu, Hawaii boasts the only royal palace in the United States of America

ʻIolani Palace, in the capitol district of downtown Honolulu in the U.S. state of Hawaiʻi, is the only royal palace in the United States used as an official residence by a reigning monarch and is a National Historic Landmark listed on the National Register of Historic Places. Two monarchs governed from ʻIolani Palace:King Kalākaua and Queen Liliʻuokalani. After the monarchy was overthrown in 1893, the building was used as the capitol building for the Provisional Government, Republic, Territory, and State of Hawaiʻi until 1969. The palace was restored and opened to the public as a museum in 1978.