Nerchinsk katorga was a system of katorga — a type of penal labour — practiced by the Russian Empire in the area of the Nerchinsk Mining District. That district embraced a large part of eastern Transbaikalia, near the border to China, in the 18th to 20th centuries. The District consisted of a variable number of industrial centres (zavody), usually operated by military administrations, the first of which, Nerchinsk, situated not far from the confluence of Nercha and Shilka Rivers, was established in the 18th century after the discovery in the area of large mineral reserves. Thus, penal labor was used to work the mines.