The Shibetsu Marsh, which stretches out within the Po River watershed, is also designated as a national natural treasure. The Po River Historic and Natural Park is a vast area spanning a total of 6.3 square kilometers that combines wetlands, the Ichanikarikariusu Ruins (a nationally designated historic site) and more. It’s a place where people can come to learn about the nature and history of Shiretoko. During May to August every year, precious wetland plants bloom in great numbers.
(Open: late April－late November)