Nerchinsk, city, SE Siberian Russia. Founded in 1654, the city was a Russian outpost in E Asia from the 17th to the 19th cent. A Russo-Chinese border treaty signed at Nerchinsk in 1689 was the first treaty concluded between China and a European power; it granted the Transbaykalia area to Russia and left the Amur valley to China. The treaty also permitted Russian trading caravans to go to Beijing; Nerchinsk became an important customs and trade center on the caravan route.