Kiritappu marsh is the second largest peat bog (3,168 ha), after Kushiro Shitugen, on the coastline of eastern Hokkaido. The central area is high moor and has been designated as a Natural Monument. A 4km belt of woods around the marsh captures the mist from the marsh, so a selection of flowers, such as Eriophorum varinatum and Hemerocallis middendorffii can be seen. Also, this site is known as an important breeding ground of A Special Natural Monument, the Japanese Crane. Together with neighboring Hichirippunuma and Mochirippunuma, this area is a Ramsar site. Kiritappu marsh faces Hamanaka bay and Biwase bay on the Pacific Ocean. There are Touhutsushima islet and Kenbokkishima islet and Kojima islet in Biwase Bay. Kenbokkishima and Kojima islets are important nesting sites for sea birds as these islets are not inhabited by people. Kojima islet has one of few colonies of Tufted Puffin in Japan, and Kenbokki islet is a large scale nesting site for Leach's Storm-petrel.