The Tönnö nature trail starts from the banks of Porvoo River and continues to the Tönnö ridge area. The terrain along the route is diverse and its attractions include an ancient shoreline, formed during the Ice Age.

Tönnö nature trail goes on the banks of Porvoonjoki river and continues to the Tönnö ridge area. The lenght of the trail is 3 kilometers and there is an information board at the start point. Nature type changes by the trail from broad leaf woodland to dryish ridge ares with boreal forest. Its attractions include an ancient shoreline formed in the Ice Age. The first ever reinforced concrete bridge in Finland, The Tönnö bridge, is also located near the trail. The bridge was completed in 1911.