Maunawili is a residential census-designated place (CDP) in the City & County of Honolulu, Koolaupoko District, Island of Oahu, Hawaii, United States. As of the 2020 census, the CDP had a population of 2,026. Situated mauka (inland or mountain side) of Kalanianaole 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 (by car or bus) from Kailua.