Štola Myší díra, Mining adit in Litice nad Orlicí, Czech Republic.

Štola Myší díra is a 36-metre water channel driven through the granite massif beneath Litice Castle in Litice nad Orlicí. It runs through the neck between Kletná hill and the castle spur above the Divoká Orlice. In 1931 it was widened, lined with concrete and fitted with a sluice; a stilling chamber and a two-metre-high, 28.8-metre-long weir stand at its outlet.

Štola Myší díra was driven through the granite massif beneath Litice Castle between 1495 and 1521, during the rule of the Pernštejn family. It was probably cut as a flood-protection work to shield the buildings in the valley below the castle from the Divoká Orlice. In 1931 the channel was widened, lined with concrete and fitted with a sluice; the wooden weir was repaired and concreted the same year. A small hydroelectric plant, the first fully automated one in Czechoslovakia, was built in 1931–1932 and began operating on 1 April 1932.

The channel is a protected cultural monument of the Czech Republic, listed apart from the small hydro plant it feeds. Its name, Myší díra ("mouse hole"), comes from the narrow 36-metre passage drilled through the granite. The adjoining weir on the Divoká Orlice, rebuilt in concrete in 1931, is 2 m high and 28.8 m long.

The channel runs through the rock neck between Kletná hill (535 m) and the Litice castle spur, where the Divoká Orlice bends around the outcrop called Hřebínek. The adit itself is 36 m long; at its outlet stands a balancing chamber founded on bedrock, and the masonry weir on the river is 2 m high and 28.8 m long. The water is led from the weir at river km 66.829 through a 90 m supply pipe with a 24.5 m head to the small hydro plant.

The channel is not a mine but a water tunnel driven through the granite of the Litice castle rock in 1495–1521 under the Pernštejn lords, probably to divert floods away from the houses in the valley below. Since 1931–1932 it has fed a small hydroelectric plant, the first fully automated one in Czechoslovakia, which began operating on 1 April 1932.