Oesel, or Esel, an island stretching across the mouth of the Gulf of Riga, in the Baltic Sea, and included within the Russian province of Livonia. It has an area of 1,010 square miles, being about 45 miles long by 30 miles broad, with a bold limestone coast and an undulating, well-watered, and well-wooded interior. Grain, flax, hemp, potatoes, and timber are the chief products, and the island is famous for a breed of small ponies. Belonging at first to the Teutonic Knights, it was occupied successively by Danes and Swedes, and ceded finally to Russia in 1721. The population is almost entirely Lutheran, and the capital, Arensburg, on the south coast, is little more than a large village.