Halltorp is one of the earliest manor houses on the island of Öland, Sweden, dating from the 11th century AD. In early documents it is known as Hauldtorp, and it is cited as one of the early Viking settlements of Öland. In earlier times it has functioned as a royal farm associated with the Swedish Crown and was considered one of the finest hunting preserves on the island. There is a relict oak forest on the present grounds which contains numerous trees that are centuries old. Halltorp is in an area rich in history and biodiversity, and most of the island of Öland has been designated as a World Heritage Site.