ORSK (Yaman-kala of the Kirghiz), a district town of Orenburg, Russia, 155 miles to the east-south-east of the capital of the government, on the right bank of the Ural, was originally founded in 1735 as the principal Russian fort against the attacks of the Kirghiz. Though this was afterwards transferred to Orenburg, the town of Orsk has increased rapidly within the last few years, owing to the fertility of the surrounding country, to immigration, and to the growth of trade with the Kirghiz. The population, only 6000 some fifteen years ago, reached 14,350 in 1880, and has since become larger.