Sinjindo Island is located at the end of Jeongjuk Peninsula in Sinjindo-ri, Geunheung-myeon, Taean-gun, Chungcheongnam-do. The island has an area of 1.06 ㎢, and is 40 km away from Taean-gun and 1km away from Geunheung-myeon. People settled on the island after Manhocheon fortified the shore during the period of King Seongjong.