Morské oko — the largest lake of the Vihorlat hills

The other Morské oko

Not to be confused with its Tatra namesake: this is Morské oko in the Vihorlat hills of eastern Slovakia, a few dozen kilometres from the Ukrainian border. It was once called the Great Vihorlat Lake. It is the largest lake of the Vihorlat and the third-largest natural lake in Slovakia after Štrbské pleso and Veľké Hincovo pleso in the Tatras. It lies at 618 m below the rocky summit of Sninský kameň (1,006 m), in the cadastres of Remetské Hámre and Vyšná Rybnica.

The lake formed as the Vihorlat’s volcanic activity was dying down: a massive landslide from the slopes of Motrogon and Jedlinka blocked the valley of the Okna stream, and water collected behind the natural barrier. It took its present form in the 1880s, when an artificial dam raised the level by 5 m: the area grew from about 7 to 13.8 ha. The lake is 750 m long and 312 m wide, with a maximum depth of 25.1 m. It is fed by six permanent springs. A 1784 map marks it as the “Muddy Lake”, the name Morské oko (Oculus Marinus) first appears on a 1792 map of Ung County, and the official name Great Vihorlat Lake was adopted in 1933.

Since 1984 the lake and the surrounding forests have been a reserve, today a 108-ha national nature reserve with the highest, fifth level of protection. It lies in the Vihorlat Protected Landscape Area and in the buffer zone of the Vihorlat primeval forest, inscribed on the UNESCO World Heritage List in 2007 among the Carpathian primeval beech forests.

What to see and do

• A walk along the shore. The western and northern shores are gentle, with fine sand; the eastern shore is steep and rocky. An information centre of the reserve operates by the lake.
• Sninský kameň. From the lake a blue-marked trail climbs to the Sninský kameň rock in about 1 h 35 min — from there you see Morské oko from above. The educational trail “Morské oko — Sninský kameň — Sninské rybníky” follows this route too.
• Malé Morské oko at 727 m — about 30 minutes on the yellow trail.
• Tourism history. The first tourist shelters in Slovakia outside the High Tatras were built in 1880 by the Beskydy section of the Hungarian Carpathian Society from Uzhhorod — by Morské oko and below Sninský kameň.

Practical information

The shortest way is from the Krivec car park (562 m) below the lake: just 15 minutes on the blue trail, a walk suitable even for families with small children. On foot from Remetské Hámre on the green trail it takes about 2 h 35 min, and from Zemplínske Hámre via the Tri tably saddle about 1 h 45 min. We recommend checking car access conditions to Krivec before you go. According to the Vihorlat PLA administration, in summer 2026 (15 June — 15 September) 21,105 visitors were counted at the lake, 1,286 of them cyclists.

Fishing, swimming and boating are forbidden in the reserve; stay on the paths and take your litter home. Entry is free.

Nearby

To the south is Zemplínska šírava, the “Slovak Sea” with its beaches. To the north are the Starina reservoir in Poloniny NP and the UNESCO-listed wooden church in Ruská Bystrá.

Official website: chkovihorlat.sopsr.sk

Photos: P.matel, Public domain, Wikimedia Commons; Milan Bališin, CC BY-SA 4.0, Wikimedia Commons; Jiří Komárek, CC BY-SA 4.0, Wikimedia Commons.