Gamgok-myeon (감곡면) (甘谷面) is a myeon located in the northernmost part of Eumseong-gun, Chungcheongbuk-do. It is bounded by Gyeonggi-do on the north and west; on Chungju-shi's Angseong-myeon on the east and Noeun-myeon on the southeast; and by Eumseong-gun's Saenggeuk-myeon on the south.
Gamgok town forms, along with Janghowon, a Twin Minicities connurbation right on the Gyeonggi-do/Chungcheongbuk-do boundary. Gamgok is east of the river and the provincial border. Janghowen is to the west and is part of Icheon-shi.
Buses from Icheon to Chungju stop in both places. The Gamgok bus terminal is near a three-way junction but down a little side lane from it - hard to find unless one knows its there or asks. The terminal is small and isn't even marked on its front, and that couldn't be seen from the street anyway. Here it is from the side with the buses: