Near the town of Kostomuksha is an area belonging to state natural reserve is situated, was founded in 1983. The reserve was made in the composition of Finnish-Russian nature reserve Friendship "in 1991. This reserve is on the border with Finland and experts from Russia and Finland are actively engaged in research and preservation of unique natural complexes of the region.

Especially valuable are the unique forest reserve, which represent a valuable genetic Fund and ideal Northern taiga. Mainly on the territory of the reserve are growing spruce and pine, but you can meet and deciduous trees. The average age of trees around 170-180 years, but there are long-lived, their age is over 300 years old.

In addition to the forest reserve is rich in lakes and, on their territory, there are approximately 250. The most beautiful lake nature reserve on the right is the Stone lake, covering an area of more than 10 thousand hectares and consisting of 98 Islands Islands and many bays and capes. Long ago, the local banks were settlements Karels, who left behind a meadow under cropland. In total, on the shores of Stone lake used to be located about 20 villages, the residents are free to communicate with neighbors – Finnish residents. From the lake originates from the eponymous river – Stone, which runs through the Park. This relatively small river – 25 km and particularly impresses tourists with a Grand King-the threshold, in the cliffs.

During the Second world war, the reserve was not affected by the fighting, but in some places still preserved their consequences.

In the Kostomuksha nature reserve inhabited by many endangered and rare animals and birds: otter, Northern forest deer, lynx, white-tailed eagle, Wolverine, Golden eagle, Swan, whooper Swan, osprey, gray crane. In the lakes and rivers of the reserve is home to the most prolific in Karelia "kamennoozerskaya" the population of grayling, lake-river whitefish and salmon.

Wishing to get to the natural reserve "Kostomuksha" we must remember that for the passage of the protected area need to obtain a special pass. In addition, the reserve is prohibited to collect herbs, seeds, mushrooms and berries, hunting, fishing, littering and harm to flora and fauna. Fires are permitted only in designated areas.