PERNAU, in Russian Pernoff, a seaport town and watering-place of European Russia, in the government of Livonia, is situated in 58° 23' N. lat. and 24° 30' E. long., 155 miles north of Riga, on the left bank of the Pernau or Pernova, which about half a mile farther down enters the Bay of Pernau, the northern arm of the Gulf of Riga. The town proper is well and regularly built, and contains two public gardens and two public parks (Salon Park and Bade Park), a town-house, a hospital, and a public library. On the right side of the river lies the suburb of Bremerseite. The harbour is small, and the depth of water on the bar under 10 feet. The exports, which consist mainly of flax (to Great Britain, France, and Portugal), linseed (to Germany), mats, and cereals, had a value of 8,220,421 silver roubles in 1880, and of 5,427,465 in 1881 (a bad year). The population was 6690 in 1863, 9525 in 1867, and 12,918 in 1881.

Founded on the right side of the river in 1255 by one of the bishops of Oesel, Pernau, with its walls and castle, soon became a flourishing place. In the 16th century it was occupied in succession by the Swedes, the Poles, and the knights of the Teutonic order. After 1599 the Poles transferred the town to the left side of the river; and in 1642 the Swedes, who had been in possession since 1617, strengthened it with regular fortifications. In 1710 it was besieged and taken by the Russians, and the fortress is now demolished.