Nerchinsk, town, Zabaykalye kray (territory), south-central Siberia, Russia. The town lies along the Nercha River just above the latter’s confluence with the Shilka.
Nerchinsk was founded as a fort in 1654. It once served as an important customs post and trading centre on the route to China, but the town declined when it was bypassed by the Trans-Siberian Railroad in the late 19th century. There are minor electromechanical and food-processing industries in the town. Pop. (2010) 14,959; (2014 est.) 14,775.