This research studied irrigation facilities and system of Ganghwado. Ganghwado is a crucial island of Ganghwa-gun County in Incheon City. It had a population of 6,0424 as of 2002. Its area covers 302㎢?, surrounded by a 91㎞ coastline. Its cultivated oand area covers about 120㎢(paddy field: 86㎢?). Ganghwado is located at the entrance to the downstream basin of the Hangang River which is situated at the heart of the Korean Peninsula. The island has served as a crucial area for traffic and military since ancient times. In particular, whenever the Korean Peninsula was engulfed by great warfares in history, Ganghwado was highlighted thus dubbed town of history. Such historical background of Ganghwado made the island push ahead with reclamation projects aimed at securing food despite its numerous unfavorable conditions. Records still remain until today on reclamation projects carried out when the Goryeo Dynasty was invaded by Mongol and during the early period of the Joseon Dynasty. The successful reclamation projects and subsequent development of cultivated land were attributed to the spread and expansion of irrigation facilities. Irrigation use facilities in Ganghwado include weirs('bo'), reservoirs, water pumping stations and tube wells. Weirs are a traditional Irrigation facility, and were able to contain water originally using bags of soil. They have been gradually replaced by sluices since the 1980s. There are some 20 reservoirs, and they have been increased since the 1970s. Reservoirs, as the most important irrigation facility, supply irrigation water to an area measuring about 3,600㏊?. There are about 20 major water pumping stations, which supply water to an area covering 2,500㏊?. They were mostly installed since the 1990s. Pumping stations in Ganghwado come in the types of riverbed reservoirs created by installing sluices at river mouths and digging riverbeds wide and deep, and of pumping fresh-water from inside sea walls. Likewise, pumping stations of Ganghwado is a facility combining a sea wall, a sluice and a riverbed reservoir. Some of pumping stations are placed at an altitude higher than riverbed reservoirs and water is pumped from them and supplied through irrigation channels attached to reservoirs. Ganghwado offers some 6,000 small and large tube wells. Most of them are small types controlled by individuals while there are 17 large tube wells with major large tube wells constructed since the 1988s. These large tube wells complement the irrigation use system of reservoirs and pumping stations. Small tubed wells, growing in number, are becoming important as actual irrigation facilities. The Ganghwado irrigation system is divided into irrigation channels that let water flow from reservoirs using altitude difference, and the water supply system pumping irrigation water using pumping stations. Since 'Deul'(paddy fields) of Ganghwa are not so expansive, these two irrigation systems are not clearly distinguished, allowing reservoirs, pumping stations and tube wells to complement each other. Irrigation facilities and systems in Ganghwado are significant in understanding agricultural irrigation being conducted in major islands of Korea.