Čertovo jezero

Čertovo jezero (Devil's Lake) is a glacial mountain lake in the municipality of Železná Ruda, Plzeň Region, right in the heart of the Šumava mountains in the Czech Republic. Together with the neighbouring Černé jezero (Black Lake), it ranks among the best-known cirque lakes of the Bohemian Forest and is the second-largest lake in the entire Šumava range.

How did the lake form?

Devil's Lake is of glacial origin: it fills a glacial cirque, and its waters are held back by a high terminal moraine ridge left behind by a glacier that once retreated from the site. This combination — a steep cirque wall on one side and a moraine dam on the other — is typical of Šumava's glacial lakes and explains why the lake reaches considerable depth despite its modest surface area.

How big and how deep is it?

The lake covers an area of 10.33 hectares and measures roughly 250 by 150 metres. It sits at an altitude of 1,030 metres above sea level, and its maximum depth reaches 37 metres — a striking figure even compared with many much larger lowland lakes. It is fed by both groundwater and small streams flowing down from the surrounding slopes.

What is the surrounding nature like?

The lake is entirely encircled by spruce forest of a primeval character, largely inaccessible to visitors outside the marked trails. Because of its unique flora, fauna and undisturbed woodland, the area was placed under protection as early as 1933, by decree of the then Ministry of Education. Today Devil's Lake lies within Šumava National Park, which secures its continued protection.

What connects Čertovo jezero with Černé jezero?

The two lakes lie barely 1.5 kilometres apart as the crow flies, although the hiking route connecting them is longer. On the ridge of Jezerní hora, between the two basins, runs the main European watershed — the boundary between the North Sea and Black Sea drainage basins. Having two large cirque lakes so close together, yet draining toward opposite ends of the continent, is a genuine rarity at this scale.

Frequently asked questions

Where is Čertovo jezero located? In the municipality of Železná Ruda, Plzeň Region, within Šumava National Park, close to the border with Bavaria.

How large is the lake? It covers 10.33 hectares (about 250 by 150 metres) and is the second-largest lake in the entire Šumava mountains.

How deep is Devil's Lake? Its maximum depth is 37 metres, making it one of the deepest lakes in the region.

Is the lake of glacial origin? Yes — it fills a glacial cirque dammed by a terminal moraine ridge.

How far is it to Černé jezero? About 1.5 kilometres in a straight line; the ridge between the two lakes carries the main European watershed.

Since when has the lake been protected? Since 1933, by decree establishing the area as a protected natural site.