Hon-maru (the main enclosure) of Naegi Castle, was located on the hilltop area of Mt. Takamori-yama (432 m, approx.1417 ft), a rocky mountain with layers of huge rocks. The Kiso-gawa River at the foot of the mountain served as a natural moat of the castle. The comparable height difference between the river and Hon-maru was about 170 m (557 ft). It has a splendid view from here. Right in front, one can see an old streetscape of a post town of Nakatsugawa along Nakasen-do road and Mt. Ena-san (2191 m, approx.7186 ft) rising high above behind that. The mountains continue into Mt. Hoko-yama (969 m, 3178 ft) (the flat area of the mountain top is called Nenoue Plateau) on the right side, while on the left side, you can overlook the Kiso mountains and Misaka Pass on old Tosando road.