Černý Důl (German: Schwarzenthal or Schwarzental) is a market town in Trutnov District in the Hradec Králové Region of the Czech Republic.

Černý Důl consists of three municipal parts (in brackets population according to the 2021 census):[2] The name literally means 'black valley', 'black mine'.

The highest point is located on the slopes of the Černá hora Mountain at 1,272 m (4,173 ft) above sea level.

The first written mention about iron ore mining in the area of today's Černý Důl is from 1383.

[4] In that time, the area was formed by three parts: Nová Ves village, settlement of Gottes Hilf, and grouping of huts called III.

After the mining ended, the population had to reorientate to linen making, spinning, agriculture and livestock, as the land consisted mostly of mountain pastures.

[3] The I/14 road (the section from Liberec to Trutnov) passes through the southern part of the municipal territory.