Mir Island is a small islet in the Geum River, close to Gongju's main historic sights. It is best treated as a gentle walk rather than a major attraction: paths cross the riverside vegetation, and seasonal plantings make it popular for photos.
Autumn is the prettiest time, when reeds and pink muhly grass soften the riverbanks. Combine it with Gongsan Fortress or the Songsan-ri burial mounds if you want a quieter pause between the bigger Baekje sites.