Sanginjoki Nature Reserve is located at a distance of about 20 kilometres from the city centre of Oulu. The area chiefly consists of former multiple-use forests, but there are also old spruce forests, wooded mires and dry esker heaths. There are ponds, mires and springs along the trails. Sanginjoki Nature Reserve offers a wide range of hiking and outdoor activities, and it is popular among berry and mushroom pickers. The forest area of Sanginjoki – which covers more than 2,500 hectares – was signed over to Metsähallitus in the spring of 2021.
The Sanginjoki forests chiefly consist of old heath forests, which become more varied thanks to the pine mires, lush wooded mires, as well as springs and small waterbodies. The Asmonkorpi old-growth forest and the old, moss-covered coniferous forest of Iso Polvikangas have remained untouched for a long time. In the Sanginjoki Nature Reserve, you can sight many rare forest bird species, such as the Siberian jay, red-flanked bluetail, three-toed woodpecker, capercaillie and the Eurasian pygmy owl.
The area is managed by Metsähallitus, Parks & Wildlife Finland, Ostrobothnia–Kainuu.