Semily District is a district in the Liberec Region of the Czech Republic. Its capital is the town of Semily, but the most populated town is Turnov.

Liberec Region is an administrative unit of the Czech Republic, located in the northernmost part of its historical region of Bohemia. It is named after its capital Liberec. The region shares international borders with Germany and Poland. Domestically the region borders the Ústí nad Labem Region to the west, the Central Bohemian Region to the south and the Hradec Králové Region to the east.