Natural Features of Oulujärvi Hiking Area

Two old pine trees in the foreground and a pine forest in the background.

In the Oulujärvi Hiking Area, you will be enchanted by the stark beauty of Lake Oulujärvi. The cries of gulls and common terns set a truly maritime mood. You can paddle into the sunset across the wide open waters of the lake.

Taking care of nature

The endless sand beaches of Lake Oulujärvi

The landscape of Lake Oulujärvi is well worth seeing, with its unique waters, beaches and pine forests. The trails of the Hiking Area go through light pine forests and on sandy banks. You can find your own favourite spot for picnic and swimming on the long sandy beaches.

Two children wading through the shallow water at a beach.The Oulujärvi Hiking Area consists of land and water areas on the island of Manamansalo and on Niskanselkä part of Lake Oulujärvi. The islands of Ykspisto, Ylä-Mulkku and Kaarresalo and parts of Honkinen, Kuostonsaari and Jylhänniemi are included in the Hiking Area. The water areas make up 64,3 of the surface area, and 14 consists of the islands and mainland.

The special natural features of Manamansalo include the lichen-covered heaths, the steep shoreline of Lake Oulujärvi, and the many clear forest lakes popular as fishing places. Pikes (Esox lucius) and perch (Perca fluviatilis) live naturally in lakes. In addition, rainbow trouts (Oncorhynchus mykiss) have been planted in lake Särkinen.

Lake Oulujärvi

Lake Oulujärvi is the fourth largest lake in Finland. It was under the continental ice sheet until about 9100 - 9400 years ago. The surface area of the lake ranges between 778 and 944 because the water level is controlled. The average depth is 7 metres, and in the deepest places it is about 38 metres.

Lake Oulujärvi flows into the Gulf of Bothnia through Oulujoki River. It is connected to Lake Nuasjärvi via Kajaaninjoki River, and receives 87% of its water from the rivers Kiehimäjoki and Kajaaninjoki. The lake is part of the water system of Oulujoki River, and the waterways of Hyrynsalmi and Kuhmo. The open water areas Niskanselkä and Ärjänselkä of Lake Oulujärvi are Finland's largest continuous open water areas on a lake.

Many of the islets on the open water areas are rocky and barren, piled up by the ice, but most islands have sandy beaches. On the edges of the large open waters, there are sandy shallows, where the Brown Trout (Salmo trutta m. lacustris ) comes to feed.

Sea of Kainuu

Oulujärvi Hiking Area is located on the shores and islands of the Niskanselkä vast stretch of water in Lake Oulujärvi. The lake has three wide stretches of water. Niskanselkä is one of the vastest lake sections in Finland, and even though the number of islands is high, they are located far from each other and most of them are small. The scenery and the living conditions are similar to those of a sea and seashores. The Sea of Kainuu even smells slightly like a sea.
Waves are often large, the ice in the winter is thick and the wind blows. In the summer, the blazing sun mercilessly heats the inhabitants of the beaches and spaces between the stones.

Lake Oulujärvi has kept changing after it closed up from Ancylus Lake 9,000 years ago. Along with the land uplift after the Ice Age, the lake has flowed towards the east, to forests and mires, thus forming the vast stretches of water called Ärjänselkä and Paltaselkä. Niskanselkä is the oldest part of Lake Oulujärvi. Oulujärvi Hiking Area is part of the Rokua Geopark area designated by UNESCO . The hiking area belongs to the network of hiking areas in Finland and Estonia.

The water area of Lake Oulujärvi still varies, as the lake is regulated for the needs of power plants. The average lake area is 925 km2, but during the course of a year, the area may vary by more than one hundred square kilometres, as the shores are shallow.

Scenery Shaped by the Ice Age

The Ice Age sorted, piled up and carried stones and sand, exposed and polished rocks, as well as built the scenery. Most of the shores in Oulujärvi Hiking Area are sandy or rocky. A sandy esker range – piled up by a meltwater stream flowing under a glacier – runs from Manamansalo Island  to Säräisniemi. The stonier esker core can be seen on Manamansalo Island. In ancient times, the wind also carried sand and piled up dunes on the island. Today, there are mounds with pine trees.

Hard Conditions on the Shores

For plants, it is challenging to grow on the sandy and gravel shores of a large lake. Waves and the wind move their substrate. The water level continues to rise and drop. In the spring, blocks of ice roll over the plants. In order to survive, the plants must be able to hold on and find new substrates. 
The lyme grass focusses on its roots: they are long and many, serving as good anchors. Even small pieces of its roots may start growing, when the ice moves the sand and the cut off roots to a new place.

The purple loosestrife thrives close to gull communities, as it utilises the nitrogen in the droppings of the gulls. The purple loosestrife manages in the harsh conditions thanks to its strong roots and ability to ensure the pollination of its flowers by modifying the shape of its flowers in order to make them suitable for various kinds of pollinators. Its seeds are small and float a long way. In the winter, they fly, with the wind, along the ice of the lake. 

Sand Forms

Over the course of time, waves and blocks of ice have crumbled the northern shore of Manamansalo Island and as a result, there are sand cliffs on the island that gradually collapse, taking trees down with them. Sand martins, which have become rare, bore their tunnel-like nests into sand cliffs. 
There are small esker ponds on Manamansalo Island. According to the old lore, the soil of the islands in Lake Kivesjärvi nearby originate from those ponds. Most of the ponds are kettle holes which were formed by huge blocks of ice when the blocks slowly melted within the esker gravel. The ponds are so deep that they extend down to the groundwater level.

Lush and Rugged Elements

On Manamansalo Island, you will see mires in low depressions and on the shores of ponds. On the larger islands of Lake Oulujärvi, you may find small flood meadows on shores. During periods of high water levels, the flood meadows receive water and nutrients from the lake. Säippäsuo Mire – which is located on Kuosto Island in Oulujärvi Hiking Area – is the lushest of the flood meadows.

Most of the forests in Oulujärvi Hiking Area consist of fairly rugged pine trees in a sandy soil. Amid the young forests of Manamansalo Island, there are also older forests where the diversity, due to the old age, can already be seen.

The forests on the larger islands are slightly more nutrient-rich. There are older and scenically valuable forests on the islands of Kuosto and Kaarresalo. These forests are important to the diversity of bird species in the area. The forest management takes into account the importance of outdoor activities, scenery and the natural world.

Pristine archipelago nature

Most of the forests in the hiking area are dry pine forests. On the islands, also spruce-mixedwood forests and older forests can be found. In the areas which are central to tourism and hiking, there are handsome pine forests and older planted forests. There are only very small areas where the forest is in its natural state. The most impressive old-growth forests can be found in Rapsunkangas and Jylhänniemi areas. Other forests in the hiking area are former landscape forests of Metsähallitus.

A narrow and stony isthmus between two water areas. To the left is a motorboat tied to the forest-covered shore.


Oulujärvi Hiking Area is interestingly located in a transition area of both the flora and the fauna. It is the southernmost inland water area where the Arctic Tern (Sterna paradisaea) and the Common Redshank (Tringa totanus) nest. The Ruddy Turnstone (Arenaria interpres) is a sea bird which is not found on any other inland water areas but this one. The Great Cormorant (Phalacrocorax carbo), on its way to the Arctic Sea, can stop at Lake Oulujärvi and stay for the whole summer. Also the Caspian Tern (Sterna caspia ) has nested several times in the area.

Other bird species typical for the area include gulls, the Common Tern (Sterna hirundo), the Black-throated Diver (Gavia arctica), the Red-throated Diver (Gavia stellata) and the Red-breasted Merganser (Mergus serrator). The most common waders are the Common Sandpiper (Actitis hypoleucos), the Wood Sandpiper (Tringa glareola) and the Little Ringed Plover (Charadrius dubius). In the dry pine forest are found, for example, the Tree Pipit (Anthus trivialis), the Common Redstart (Phoenicurus phoenicurus), the Eurasian Cuckoo (Cuculus canorus) and the Mistle Thrush (Turdus viscivorus).

Sea Birds on Inland Waters

Oulujärvi Hiking Area interlocks with the Lake Oulujärvi reserve of bird islands. Waterfowl are abundant and rich in species. Gulls and terns have thriving nesting communities, and there are good conditions for waders on the wetlands of the shores. Birds, such as the ruddy turnstone and the Caspian tern – which are also sighted on Lake Oulujärvi but which usually thrive in sea areas – show that the Sea of Kainuu is worth its name. During the nesting period, please do not enter the rocky and gravel shores.

Out of the lake’s bird species, the lesser black-backed gull (Larus fuscus) is the most Finnish species – roughly 50 per cent of its subspecies ssp. fuscus nest in Finland. The number of these birds has decreased a great deal, which is why nesting in the Lake Oulujärvi area is important to them.

The Caspian tern (Sterna caspia) is a very large tern, whose loud croak is far from elegant. Unlike the other terns, these birds also nest as individual couples.

Fishing Waters

In Oulujärvi Hiking Area, you can go fishing on Lake Oulujärvi and at the ponds of Manamansalo Island. All fish species typical of the region reproduce in Lake Oulujärvi and in rivers that empty their waters into the lake. The smelt, which is the official fish species of Kainuu Region, swims in schools. Smelts are small fish that are very important to the lake, as pikeperches feed on them. Lake Oulujärvi has strong populations of perch, pike, pikeperch and vendace. Trout also prey on schools of vendace in the vast open stretches of the lake. In addition to recreational fishing, commercial fishing is also carried out on the lake. Read more about fishing in Oulujärvi Hiking Area.

The Manamansalo camping site offers you a pleasant base for your holiday trip. The camping site has a caravan site, cabin accommodation, saunas by reservation and a café-restaurant. 

Oulujärvi Hiking Area

  • Established 1993
  • Area 80 km²

Publications of Oulujärvi Hiking Area

Publications of Oulujärvi Hiking Area (