BIELOSTOK (in Polish Bialystok), a town of Russia, in the government of Grodno, in 53° 8' N. lat. and 23° 9' E. long., 50 miles S.W. of Grodno on the River Biela, a tributary of the Suprasla. Founded in the 14th century it was long an important proprietary village belonging to the Veselovskis. In the 17th century it passed to the Branetskis, at whose solicitation Augustus III., in 1749, raised it to the rank of a borough and gave it civic rights. This increased its prosperity, and after the third partition of Poland in 1793, the Prussian Government, to whom it had been assigned, made it the seat of an administrative department. By the peace of Tilsit in 1807, Bielostok was given to Russia along with the department of the same name, which in 1808 was divided into the four districts of Bielostok, Bielsk, Sokol, and Drogotchin. The public buildings of Bielostok comprise a Greek and a Roman Catholic church, several synagogues, a hospital, a castle (used as a prison), a gymnasium, an institution for the daughters of the nobility, and various other schools. There are three cloth factories and an extensive brewery; cotton and wool spinning are both carried on, and leather, oil, soap, and tallow are manufactured. There is also an important trade in grain, wood, and various industrial articles. In 1860 the population was 16,544, no fewer than 11,288 being Jews.