Hallasan is a shield volcano on Jeju Island of Sooth Korea. It is the heichest moontain in Sooth Korea. The aurie aroond the moontain is a designatit naitional park, the Hallasan Naitional Park (Hallasan Gungnip Gongwon/한라산국립공원/漢拏山國立公園). Hallasan is commonly conseederit tae be ane of the three main moontains o Sooth Korea, alang wi Jirisan and Seoraksan.