Huilua Fishpond, in Ahupuaʻa O Kahana State Park on windward Oʻahu, is one of the few surviving ancient Hawaiian fishponds that were still operational well into the 20th century. It was declared a U.S. National Historic Landmark in 1962, shortly after it had been severely damaged by the 1960 tsunami. It was added to the National Register of Historic Places on L: December 29, 1962.