Ralsko is a town in Česká Lípa District in the Liberec Region of the Czech Republic. It has about 2,300 inhabitants. It comprises area of the former military training area with Hradčany Air Base. Ralsko is the fourth largest municipality in the country by area.

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.