Ozegahara is the main feature of Oze. It is the huge marshland surrounded by over 2,000 high mountains. The marshland itself is about 1,400m high from the sea level. The marshland makes many ponds and gallery forest. Water from the mountains gather at Ozegahara and run into Sanjo Falls.

Ozegahara is very famous for Asian Skunk cabbage and Daylily. Skunk Cabbage blooms from May to July. Oze was formed in the Ice age. The plants of Oze are mostly cold district plants that started habituating during the Ice age. When the ice age was over, most of the plants are replaced from warm land plants. However, Oze was located high up in the mountain, those plants of ice age survived today.