Ytre Oslofjord

Bastøy Lighthouse (Norwegian: Bastøy fyr) is a coastal lighthouse in Horten Municipality in Vestfold county, Norway. It is located on the island of Bastøy in the Oslofjorden, about 4 kilometres (2.5 mi) southeast of the town of Horten. It was established in 1840 and originally consisted of a stone house with a low tower. It was replaced by an automated light in 1986.

Bastøy Prison (Norwegian: Bastøy fengsel) is a low-security, male-only prison on Bastøy Island, Norway, located in the Horten municipality about 75 km south of Oslo. The prison is on a 2.6 km2 island and hosts 115 inmates making it the largest low-security prison in Norway. Arne Kvernvik-Nilsen, governor of the prison, leads a staff of 69 prison employees. Of this staff, only 5 employees remain on the island overnight. The prison is about one hour commuting distance from Oslo. Once a prison colony for young boys, the facility is trying to become "the first ecological prison in the world". Recidivism has been reported at 16%, compared to the European average of around 70%. Inmates are housed in wooden cottages and work the prison farm. During their free time, inmates have access to horseback riding, fishing, tennis, and cross-country skiing. The only access to the prison is from a ferry that departs from Horten.

Bastøy is an island in Horten Municipality in Vestfold county, Norway. The 2.23-square-kilometre (550-acre) island is owned by the government and it has no permanent residents, however, Bastøy Prison, a minimum-security prison, is located on the island, so there are always temporary residents on the island. The Bastøy Lighthouse was established on the island in 1840.

The Moss–Horten Ferry is an automobile ferry on Norwegian National Highway 19 that connects the counties of Vestfold and Østfold at the quays of Moss and Horten. The 10.5 kilometres (6.5 mi) crossing of Oslofjord is performed with three double-ended ferries operated by Bastø Fosen, making the crossing in 30 minutes, with departures twice an hour. In 2008 the line had a daily ridership of 3720 people and 4086 vehicles. It is the most trafficked car ferry line in Norway.

German submarine U-1273 was a Type VIIC/41 U-boat of Nazi Germany's Kriegsmarine during World War II. She was ordered on 23 March 1942, and was laid down on 7 June 1943, at Bremer Vulkan-Vegesacker Werft, Bremen-Vegesack, as yard number 68. She was launched on 10 January 1944, and commissioned under the command of Oberleutnant zur See Karl-Heinz Voswinkel on 16 February 1944.

Viken (Old Norse: Vík or Víkin), or Vika, was the historical name during the Viking Age and the High Middle Ages for an area of Scandinavia that originally surrounded the Oslofjord and included the coast of Bohuslän. Its definition changed over time, and from the Middle Ages, Viken included only Bohuslän.During the Viking Age, Viken was defined as the strait running between Norway and the southwest coast of Sweden and the Jutland peninsula of Denmark. It is located in what is now southeastern Norway and the southwestern Swedish province of Bohuslän. During the Viking Age, Viken was the northernmost Danish province. Control over Viken shifted between Danish and Norwegian kings in the Middle Ages, and Denmark continued to claim Viken until 1241. Viken was also controversially chosen as a neologistic name for the administrative region consisting of a merger of the counties of Akershus, Buskerud, and Østfold.

Alby gård is the oldest farm on Jeløya in Moss, Norway. The farm has roots back to early Viking Age. The main building was given its present shape after a fire in 1866, and in 1963 the municipality bought the farm of the last private owner, shipowner Biørn Biørnstad. Today, Galleri F 15 rents the main building, while the stabburet can be used by the county governor such as Jeløy Naturhus, and the land is leased away. Jeløy is also a special area with unique nature. The Søre Jeløy landscape conservation area was created in 1983, and helps to preserve the historic characteristic of the landscape.

Punkt Ø AS is a Norwegian art institution founded in 2006 with Østfold county as its largest shareholder. The institutions goal is to promote knowledge and understanding for Norwegian and international contemporary art. Punkt Ø runs Galleri F 15 and Momentum, a Nordic biennial for contemporary art.

Gullholmen Lighthouse (Norwegian: Gullholmen fyr) is a coastal lighthouse in the municipality of Moss in Østfold, Norway. The lighthouse is located in the outer Oslofjord, off the island Jeløya. It was established in 1894, and replaced by a light in 1984.

Jeløy Radio (Norwegian: Jeløy radio) is a radio station situated on the peninsula of Jeløya in Moss Municipality in Østfold county, Norway. It currently only operates as an unstaffed coast radio station operating marine VHF radio connected to Tjøme Radio and a Navtex service operated from Vardø Vessel Traffic Service Centre.

Åsgårdstrand Church (Norwegian: Åsgårdstrand kirke) is a parish church of the Church of Norway in Horten Municipality in Vestfold county, Norway. It is located in the town of Åsgårdstrand. It is the church for the Åsgårdstrand parish which is part of the Nord-Jarlsberg prosti (deanery) in the Diocese of Tunsberg. The red brick church was built in a long church design in 1969 using plans drawn up by the architects Eva and Bernt Mejlænder. The church seats about 250 people.

Tjøme Radio is a coast radio station in Horten, Norway. Operated by Telenor Maritim Radio, it has the responsibility for Skagerrak coast between Søgne and the Norway–Sweden border. It also covers the lake Mjøsa. Established in 1905 by the Royal Norwegian Navy, it became a civilian installation five years later. The station was located in Tjøme until 2008.