Hallyeohaesang National Marine Park was designated as the first national marine park in 1968 and covers the area between Jisimdo Island in Geoje and Odongdo Island in Yeosu with six separate districts including Geoje, Tongyeong, Sacheon, Hadong, Namhae and Odongdo Island. It spans over an area of 535.676 ㎢ and the ocean accounts for 76% of the total area. The outstanding view created by the sea and land attracts over 1 million visitors every year.

Geoje is made up of 10 inhabited islands and 50 uninhabited islands. Two-thirds of the area is included in Hallyeohaesang National Marine Park, featuring Haegeumgang Islets, designated as Scenic Site No. 2, and Daebyeongdaedo Island & Sobyeongdaedo Island, one of the most stunning points of Hallyeo Waterway. Also, the drive on the coastal road between Yeocha and Hongpo offers a breathtaking view of Dadohae Islets unfolding from the peak of Cheonjangsan Mountain and Nojasan Mountain.