The Yttergrund Lighthouse was built to illuminate a dark fairway in the Bothnian Sea

By the late 19th century, the Central Bothnian Sea was one of the darkest areas in the Gulf of Bothnia. Between the lighthouses of Säppi and Sälgrund was a 90-kilometre stretch of unlit sea lane.

In 1880, it was decided to build a lighthouse on the island of Södra Yttergrund in Kristiinankaupunki. Yttergrund Island already had an old pilot station with its associated buildings.

Since the construction was delayed for more than a decade, many ships ran aground on reefs near the island. Although a few lucky ships were able to continue their journey, some sank and remained on the seabed as shipwrecks.

The lamp of the unique iron lighthouse is lit

The construction of a modern iron lighthouse by the Helsinki-based construction company Kone & Siltarakennus began in 1890. Parts were assembled piece by piece in the factory yard and once completed, disassembled again before being shipped to Yttergrund. Construction work on the island began in the spring of 1892 and the various parts were assembled onto a large stone plinth and steel frame. The new lighting equipment was ordered from France.

Lighthouse frame under construction in the Sörnäinen factory yard in Helsinki in 1891.

The lamp of the Yttergrund Lighthouse was first lit on September the 18th, 1892 and carried 14 nautical miles out to sea. At the time of its completion, the 10-storey, 41-metre high lighthouse was the tallest in the Nordic countries. Its light is 43.6 metres above the ground.

The construction drawings of this unique lighthouse tower were exhibited at the Paris World Exhibition in 1900 and the International Industrial Exhibition in St. Petersburg in 1908.

Activities on the lighthouse island of Yttergrund

Before the construction of the lighthouse, pilots lived on the island. When the lighthouse was completed, a lighthouse master and three lighthouse keepers were hired and lived on the island also. They had their residential buildings near the old pilot station and lighthouse in the early 1890s. Unlike many other barren lighthouse islands, the houses were surrounded by small gardens and the keepers had the opportunity to keep a few domestic animals also.

The completed lighthouse on Yttergrund Island in 1892.

Life on the island began to quieten when pilot operations ceased in the 1920s. The beacon light became gas-powered in 1931 when two of the lighthouse keeper’s positions were also decommissioned. After automation in 1963, all the remaining positions were terminated, and the island's operations closed down completely.

Although the yard is now deserted, the buildings have been rented to various societies. Nevertheless, the lighthouse is still operational and guides seafarers for distances of up to 16.5 nautical miles out at sea. The lighthouse is currently Finland's third tallest after the lighthouses of Bengtskär and Suomenlinna.

Yttergrund Lighthouse.

Why and how is this location protected?

The Yttergrund Lighthouse is an exceptional building and is one of the best preserved historical lighthouse buildings in Finland, in appearance, interior, and technology. The well-preserved yard adds value to the site.

This lighthouse island is one of the lighthouse and pilot islands of the Kvarken Archipelago, which are nationally significant built cultural environments. In addition, the island is surrounded by the Siipyy Archipelago nature reserve.

Learn more about Yttergrund from the webpages of the Finnish Heritage Agency!


The island is a short boat ride from Siipyynniemi Headland across a narrow strait and can be reached by private or rental boat. The island has a harbour.

Finnish Heritage Agency's mapservice

N: 6885033, E: 201248 (ETRS-TM35FIN)