Samosir

Samosir, or Samosir Island, is a large volcanic island in Lake Toba, located in the north of the island of Sumatra in Indonesia. Administratively, Samosir Island is governed as six of the nine districts within Samosir Regency. The lake and island were formed after the eruption of a supervolcano some 75,000 years ago. The island was originally a peninsula connected to the surrounding caldera wall by a small isthmus, which was cut through by the Tano Ponggol Canal in 1907 to aid navigation.

At 630 square kilometres (243 sq mi), Samosir is the largest island within an island, and the fourth largest lake island in the world. It also contains two smaller lakes, Lake Sidihoni and Lake Aek Natonang. Across the lake on the east from the island lies Uluan Peninsula. The island was historically linked to the mainland of Sumatra on its western part by a narrow isthmus connecting the town of Pangururan on Samosir and Tele on mainland Sumatra, but it was split by the Tano Ponggol Canal and bridge in 1906, which was widened in 2019. Tele consequently offers one of the best views of Lake Toba and Samosir Island. One of the most important objects on the island is a Lutheran church, and opposite it is a huge hill.