Černé a Čertovo jezero

Černé and Čertovo Lakes are a pair of glacial lakes in the Šumava mountains of the Czech Republic, close to the town of Železná Ruda near the border with Bavaria. Both lakes formed as a result of glaciation at the end of the Tertiary period and are considered among the most valuable evidence of Quaternary glacial activity in the country, surrounded by well-preserved terminal and lateral moraine ridges that today form a nationally significant nature reserve.

How did Černé and Čertovo Lakes form?

Both lakes owe their existence to snow avalanches that accumulated on mountain slopes and gradually developed into small alpine glaciers. Around 12,000 years ago, as the climate began to warm, these glaciers started melting and pushed large quantities of rock and gravel ahead of them. This debris built up into powerful moraine ridges that held back the meltwater, giving rise to the two lakes seen today.

What sets the two lakes apart?

Černé jezero (Black Lake) is the largest lake in the entire Šumava range by surface area, covering almost 19 hectares at an elevation of roughly 1,008 metres above sea level. It is also the deepest lake on the Czech side of the range, reaching a depth of more than 40 metres. Its name comes from the dark colour of its water, an effect created by the reflection of the dense forests surrounding it.

Čertovo jezero (Devil's Lake) lies on the southern slope of Jezerní mountain, at an elevation above 1,030 metres. It is smaller, covering just over 10 hectares, with a maximum depth of nearly 37 metres. What makes it unique is its drainage basin: it is the only Šumava lake that belongs to the Danube watershed, while the rest of the region's lakes drain toward the Elbe.

Why is this a worthwhile place to visit?

Both lakes lie within Šumava National Park and are popular destinations for hiking trails winding through the region's mountain forests. The surrounding landscape has retained its natural, largely untouched character — dense spruce forests, rocky ridges, and quiet, dark-surfaced waters typical of one of Central Europe's oldest mountain ranges. The area also holds significant geological and ecological value, drawing hikers, landscape photographers, and anyone interested in the region's glacial history.

Their proximity to Železná Ruda makes the lakes relatively easy to reach, with the town serving as a natural base for both hikers and cyclists exploring the Czech side of Šumava. Because the area is a protected nature reserve, movement off the marked trails is restricted, a measure aimed at preserving the unique ecosystem of the lakes and the surrounding peat bogs.

Frequently asked questions

Which lake is bigger, Černé or Čertovo? Černé jezero is larger, deeper, and recognized as the largest lake in all of Šumava.

Which river basin does Čertovo jezero belong to? Unlike every other Šumava lake, it drains into the Danube basin rather than the Elbe.

Are the lakes of glacial origin? Yes, both formed as a result of glaciation and are surrounded by well-preserved moraine ridges.

Where exactly are the lakes located? In the Šumava mountains near Železná Ruda, close to the Czech-Bavarian border.