Laka lake, called also Pleso (Tarn), lies on the slope of the mountain Debrník (1,337 m), which is also called Plesná, near the border between the Czech Republic and Germany, about 10 kilometres south-east of the town Železná Ruda, 1,096 m a.s.l.

It is the highest located and the smallest morainic lake in the Šumava mountains (Bohemian Forest) - five of the lakes are on the Czech side of the border - Laka, Černé Jezero (Black Lake), Čertovo Jezero (Devil's Lake), Plešné Jezero lake and Prášilské Jezero (Prášily Lake); three are in Germany.

The area of the lake is 2.78 ha (it has rectangular shape) and its maximal depth is 3.9 m. The typical feature of this lake are peaty isles floating on the surface.
Two small brooks feed the lake and only one - the Jezerní Potok (Lake Stream) - takes water out of the lake into the Křemelná river.

The blue marked path leads from the parking-lot in the village Nová Hůrka (about 6 km east of Železná Ruda) to the lake (5.5 km). The green sign from Železná Ruda joins the red one about 1 km behind the town (15 km to the lake).