Gaeun is an eup in Mungyeong, Gyeongsangbuk-do, South Korea. It was formerly a center of coal-mining, but the last mines closed in the 1990s. The dominant local industries are now tourism and agriculture. There are also several operating kilns. Gaeun occupies an area of 152.4 km2, of which more than 80% is vacant land, largely rugged hill country. These hills are home to a variety of wild animals including deer and wild boars.