Horn is a municipality in the district of Arbon in the canton of Thurgau in Switzerland. Horn is an exclave of Thurgau, enclaved in the canton of St. Gallen. History Horn is first mentioned in 1155 as Horna. The Kehlhof in Horn was built in the 9th century, probably for the Diocese of Constance. In 1463, the Bishop of Constance acquired the entire bailiwick of Horn. Until 1798 the city was under the court at Arbon, where the Bishop held the high and low courts. The geographic and administrative municipalities were established in 1816, and in 1870 merged into a combined municipality. Horn was in the parish of Arbon. In 1877 a shared chapel was established. Then, in 1911 the Catholic parish was established, followed by a Reformed parish in 1920. In the 19th century the local economy was dominated by fishing, weaving and handicrafts. In 1824 a steamship company began providing regular service, which allowed the economy to grow. Bad Horn in Horn was advertised as a spa and health resort. Towards the end of the 19th century cattle, dairy farming and fruit growing became common in the municipality. After the opening of the SBB line Romanshorn-Rorschach in 1869, the bleaching company, Radun AG (1888), and the oil and fat factory Sais (1916–17), were established in Horn. By 1920, industrial companies displaced much of the agricultural sector. After Radun AG closed the mill in 1989 and the oil factory shut down in 2000, only Unisto AG (later specializing in security seals, name badges and brand profiling) as well as Sabo Specialities, successor of Sais, continued to provide manufacturing jobs. Geography Horn has an area, , of . Of this area, or 41.3% is used for agricultural purposes, while or 8.7% is forested. Of the rest of the land, or 50.0% is settled (buildings or roads), or 0.6% is either rivers or lakes and or 0.6% is unproductive land. Of the built up area, industrial buildings made up 22.7% of the total area while housing and buildings made up 9.3%. Power and water infrastructure as well as other special developed areas made up 7.0% of the area while parks, green belts and sports fields made up 11.0%. Out of the forested land, 4.7% of the total land area is heavily forested and 4.1% is covered with orchards or small clusters of trees. Of the agricultural land, 38.4% is used for