Photo: Tirolerbergwelten·CC BY-SA 3.0· Wikimedia Commons
Islands / Fredrikstad / Rauer
A military island in the Oslofjord, about 3 km², holding Rauøy fort as part of the Oslofjord fortress; under fire during the German attack of 9 April 1940. Five nature reserves were established in 2010, and the bedrock holds a distinctive rhomb porphyry conglomerate.
Rauer, also called Rauøy, lies on the western side of the Oslofjord off Fredrikstad. Keep well off; this is a military area. Look for the red-brown rock: much of the island is a distinctive rhomb porphyry conglomerate that gives the cliffs their own colour. The fort installations are spread through the terrain.
Five nature reserves (established 2010), plus military area. The boundaries and the rules are in Naturbase, and they are worth checking before you land anywhere outside the marked areas.
Military area; landing is normally not permitted, so check current restrictions.
No scheduled boat comes here. You will have to find the nearest public quay yourself, and the rest is your own boat or a kayak. Check the wind and wave forecast before you set out; the open stretches in the outer fjord turn unpleasant in a fresh breeze.
Rauøy fort was built as part of the Oslofjord fortress, the defence works meant to close the approach to the capital.
During the German attack on 9 April 1940 the fort was warned and opened fire, without hitting anything. The island surrendered the next day, 10 April 1940.
The island has been a military area for a long time and belongs entirely to the Armed Forces.
Rauer covers about 3 km², with a high point of 51 metres above sea level. It remains a military area with restricted access. Several nature reserves lie along the west side, established to protect seabirds, flora and the unusual geology.
Rauer is a military area, and landing is normally not permitted. Check the current military restrictions before planning anything near the island.
**Protection:** Five nature reserves were established on the island on 16 April 2010. The largest, Rauer nature reserve on the west side, covers 99.4 hectares (994 dekar). The reserves protect seabirds and geology, and access bans in the breeding season may apply for part of the year. Both the conservation regulations and the military restrictions carry legal force; verify the exact dates and boundaries in Naturbase and with the Armed Forces before going anywhere near, and do not guess.
Rauøy fort fired on the German ships on 9 April 1940 and missed. The island surrendered the following day.
The whole island is given over to the Armed Forces: a military island in the middle of one of the busiest boating fairways in the country.
The rhomb porphyry conglomerate is a geological rarity: crushed rhomb porphyry cemented back together along the Oslofjord fault zone, with golden lichen spread across the red-brown rock.
Oslo Sea Experience passes Rauer on its private fjord trips from Tjuvholmen.
The Norwegian version notes which facts were taken from each source: Rauer på norsk.