The origins Ryn are inextricably linked with the castle, built by the Teutonic Knights in the fourteenth century, on the isthmus between two lakes, most likely in place of tribe Galind castle. Along with the castle bailey developed, which marked the beginning of the prospective town. At the end of the fourteenth century Ryn became the capital komturship. Commander, as the head lock and manage subordinate goods. He was responsible for collecting, had judicial powers and above all, was the chief commander of the military district and the head of the religious community. In addition to the military significance Ryn served as administrative - economic, supplying in fish, honey and wild game meat. The commander of Ryn managed a Lecu (Giżycko) castle, Szestno castle and Barciany castle, a large ship, several smaller fishing boats and a steel mill . In view of the economic development arose numerous farms, sawmills and mills. "Thirteen Years" War ended with the Treaty of Toruń 1466 Ryn left within the Teutonic Order. Along with the castle developed the castle bailey settlement.
In the sixteenth century Ryn became the administrative center. After the liquidation of the Teutonic Order was established here district office of Prussia. In 1723 the town received city rights, which contributed greatly to its development. Almost to the end of the eighteenth century Ryn was a Polish town. In the nineteenth century, began to conduct systematic Germanization action that led to the fact that during the plebiscite in 1920 for Polish did not fall nor one vote. In the interwar period Ryn became famous as a health resort. The town operated six hotels, numerous nightclubs, dance halls, bars, swimming pools and steam rooms. It was possible to get here by steamboats, postal buses or narrow-gauge railway. Currently Ryn is one of the most beautifully situated cities in the Mazuria and one of the most important tourist centers in the region. Many attractions in the town and the surrounding area make it worth coming here for longer.