Maunawili is a residential census-designated place in the City& County of Honolulu, Koʻolaupoko District, Island of Oʻahu, Hawaii, United States. As of the 2020 census, the CDP had a population of 2,026. Situated mauka of Kalanianaʻole Highway between Castle Junction and Castle Hospital, Maunawili is nearly all private homes, schools, and a few churches; horse stables complete the rural setting. There are no commercial establishments. However, residents are only minutes from Kailua.