
Saltholm (; ''Salt Islet'') is a Danish island in the
Øresund
Øresund or Öresund (, ; ; ), commonly known in English as the Sound, is a strait which forms the Denmark–Sweden border, Danish–Swedish border, separating Zealand (Denmark) from Scania (Sweden). The strait has a length of ; its width var ...
, the
strait
A strait is a water body connecting two seas or water basins. The surface water is, for the most part, at the same elevation on both sides and flows through the strait in both directions, even though the topography generally constricts the ...
that separates
Denmark
Denmark is a Nordic countries, Nordic country in Northern Europe. It is the metropole and most populous constituent of the Kingdom of Denmark,, . also known as the Danish Realm, a constitutionally unitary state that includes the Autonomous a ...
and
Sweden
Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...
. It is located to the east of the Danish island of
Amager
Amager ( ), located in the Øresund, is Denmark's most densely populated island, with more than 216,000 inhabitants (January 2022). The protected natural area of ''Naturpark Amager'' (including Kalvebod Fælled) makes up more than one-third of the ...
in
TÃ¥rnby
TÃ¥rnby () is a town in Denmark, the seat of TÃ¥rnby Municipality in the Capital Region of Denmark. It is located approximately south of central Copenhagen on the island of Amager. Neighbouring settlements include the Copenhagen suburb of S ...
municipality and lies just to the west of the sea border between Denmark and Sweden. The island is 7 km long and 3 km across at its widest point. With an area of 16 km
2, it is Denmark's 21st largest island. Saltholm is very flat; its highest point stands only 2 m (6 ft) above sea level, rendering it vulnerable to flooding if persistent east winds cause a tidal surge in the
Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...
. It is a relatively new landmass in geological terms, having risen from the sea about 4,000 years ago due to
post-glacial rebound
Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound an ...
, and is surrounded by a large area of shallow water (of 2 m depth or less) that covers an area of . A series of islets, inlets and rock deposits from the last
ice age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...
appear at the south end of the island.

Its neighbouring island to the south is the
artificial island
An artificial island or man-made island is an island that has been Construction, constructed by humans rather than formed through natural processes. Other definitions may suggest that artificial islands are lands with the characteristics of hum ...
Peberholm
Peberholm ( , ()) is a small artificial island in the Danish part of the Øresund strait, created as part of the Øresund Bridge connecting Denmark with Sweden. Peberholm lies approximately 1 km south of the larger natural island of Salthol ...
(''Pepper Islet''), which is a part of the
Øresund Bridge
The Øresund or Öresund Bridge is a combined List of road–rail bridges, railway and motorway cable-stayed bridge across the Øresund strait between Denmark and Sweden. It is the second longest bridge in Europe and combines both roadway and r ...
and was named to complement Saltholm. Sometimes, Saltholm and its neighbouring island to the north,
Ven
Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in the Caribbean Sea. It comprises an area of , and its popul ...
, are referred to as the Øresund Islands.
Flora and fauna

Saltholm's vegetation is dominated primarily by grasses, with its landscape consisting mainly of flat chalk meadowlands and coastal meadow. There are few trees on Saltholm, clustered mainly in two places in the north and south-west of the island.
The island has a rich variety of flora, notably
motherwort (''Leonurus cardiaca''),
henbane
Henbane (''Hyoscyamus niger'', also black henbane and stinking nightshade) is a poisonous plant belonging to tribe Hyoscyameae of the nightshade family ''Solanaceae''. Henbane is native to Temperate climate, temperate Europe and Siberia, and natu ...
(''Hyoscyamus niger''),
blue iris
''Iris spuria'', or blue flag, is a species of the genus Iris, part of the subgenus '' Limniris'' and the series '' Spuriae''. It is a rhizomatous perennial plant, from Europe, Asia and Africa. It has purple or lilac flowers, and slender, elong ...
(''Iris spuria'') and
chickweed
''Stellaria media'', chickweed, is an annual flowering plant in the family Caryophyllaceae. It is native to Eurasia and naturalized throughout the world, where it is a weed of waste ground, farmland and gardens. It is sometimes grown as a salad ...
.
["Saltholm". ''Aschehoug's Leksikon''. Aschehoug (Egmont), 2008]
Saltholm is a protected nature reserve for wild birds which nest in large numbers on the island. The southern part of the island, an extensive
salt marsh
A salt marsh, saltmarsh or salting, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. I ...
, is protected under the
Ramsar Convention
The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar site, Ramsar sites (wetlands). It is also known as the Convention on We ...
. The island as a whole, along with the surrounding area of sea, has been designated a nature reserve by the
European Union
The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are Geography of the European Union, located primarily in Europe. The u ...
, as well as an
Important Bird Area
An Important Bird and Biodiversity Area (IBA) is an area identified using an internationally agreed set of criteria as being globally important for the conservation of bird populations.
IBA was developed and sites are identified by BirdLife Int ...
(IBA) by
BirdLife International
BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding i ...
.
Mussel
Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...
beds,
eel grass, snails, crustaceans and fish in the shallow waters around the island provide an important food source for water birds. Because of its importance as a wildlife sanctuary, access to Saltholm and its surrounding waters is strictly controlled. Access to the island is via a small harbour at Barakkebro, at the north end of Saltholm.
The island is Denmark's largest grazing area for geese, some 7,000 of which visit during the summer. Around 3,500 juvenile swans also live on the island in the summer, with some 2,000 wintering there. 10,000–12,000 ducks breed and graze on Saltholm during autumn and late winter/spring. Saltholm is also home to Europe's largest breeding colony of
eider
The eiders () are large seaducks in the genus ''Somateria''. The three extant species all breed in the cooler latitudes of the Northern Hemisphere.
The down feathers of eider ducks and some other ducks and geese are used to fill pillows and qu ...
s; 15,000 live on the island during the spring and some 7,000–8,000 are hatched on the island each year.
File:Aerial view of Saltholm - 1.jpg,
File:Aerial view of Saltholm - 2.jpg,
File:Saltholm and Oresund bridge.jpg,
History

Humans have lived in small numbers on Saltholm since the Middle Ages and probably before. The population has decreased from a peak of 298 people in 1916, when the island was fortified during
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
, to two people .
The existence of the island is first attested in 1230, when King
Valdemar II of Denmark
Valdemar II Valdemarsen (28 June 1170 – 28 March 1241), later remembered as Valdemar the Victorious () and Valdemar the Conqueror, was King of Denmark from 1202 until his death in 1241.
In 1207, Valdemar invaded and conquered Bishopric of L� ...
is recorded as having given Saltholm to Bishop
Niels Stigsen of the see of
Roskilde
Roskilde ( , ) is a city west of Copenhagen on the Danish island of Zealand. With a population of 53,354 (), the city is a business and educational centre for the region and the 10th largest city in Denmark. It is governed by the administrative ...
. For centuries, the island was used to quarry
limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
, which was used in nearby
Copenhagen
Copenhagen ( ) is the capital and most populous city of Denmark, with a population of 1.4 million in the Urban area of Copenhagen, urban area. The city is situated on the islands of Zealand and Amager, separated from Malmö, Sweden, by the ...
and elsewhere; in 1289, the town lord of Copenhagen is recorded to have granted quarrying rights on Saltholm and quarrying continued until as late as 1935.
The island was also traditionally used as pasture land for the cattle of the people of the nearby Danish island of
Amager
Amager ( ), located in the Øresund, is Denmark's most densely populated island, with more than 216,000 inhabitants (January 2022). The protected natural area of ''Naturpark Amager'' (including Kalvebod Fælled) makes up more than one-third of the ...
. The cows of Saltholm were commemorated in the late 19th century by the Danish painter
Theodor Philipsen, who travelled frequently to the island to paint its cattle and treeless landscapes.
Saltholm was used as a
quarantine
A quarantine is a restriction on the movement of people, animals, and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have bee ...
station between 1709 and 1711 when Copenhagen suffered
plague and
cholera
Cholera () is an infection of the small intestine by some Strain (biology), strains of the Bacteria, bacterium ''Vibrio cholerae''. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea last ...
outbreaks. Travellers wishing to land in the city were required to stay in quarantine on the island for 40 days. In 1873, a private company, the Saltholmlaug, acquired the island from the state and still owns it today.
The island's position in the middle of the Øresund gave it some military significance during the two World Wars. In 1912, the Danish government constructed the
Flakfortet (sand-shoal fort) on the Salthom Flak sands just north of the island proper, stationing a number of artillery pieces ranging in calibre from 47 mm to 290 mm. Most of the guns were mounted on
barbette
Barbettes are several types of gun emplacement in terrestrial fortifications or on naval ships.
In recent naval usage, a barbette is a protective circular armour support for a heavy gun turret. This evolved from earlier forms of gun protection ...
carriages and protected by armoured shields and concrete and earthen ramparts. The fort was still active at the start of
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
; although old, its guns were still seen as a strong deterrent.
Saltholm was the site of an incident resulting in the loss of the British submarine
HMS ''E13'', which ran aground on the island on 17 August 1915 due to a faulty compass. Two days later, two German destroyers attacked the submarine while it was still stranded on the shoreline as the crew worked to refloat the vessel. Fifteen of the submariners were killed before Danish torpedo boats intervened to deter the attackers. The violation of the country's neutrality outraged the Danish government, prompting a diplomatic protest to the Germans, and the casualties were given high-profile official funerals by the Danish navy. The surviving crew were interned in Denmark until the end of the war in November 1918, and the wrecked submarine was scrapped. The commander of the ''E13'', Lt Cdr
Geoffrey Layton
Admiral Sir Geoffrey Layton, (20 April 1884 – 4 September 1964) was a Royal Navy officer. He was in command of the submarine when, under attack from German vessels, it ran aground off the Danish coast during the First World War. Despite thi ...
, went on to have a distinguished career in the
Royal Navy
The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...
and commanded the British
Eastern Fleet during the Second World War.
The island was for many years considered as a possible location for a new international airport and fixed link between Denmark and Sweden. The nearby
Copenhagen Airport
Copenhagen Airport, Kastrup (, ) is an international airport serving Copenhagen, the capital of Denmark, as well as the wider Øresund Region, including Zealand and the southern Sweden, Swedish province of Scania. In 2023 it was the largest ai ...
at
Kastrup
Kastrup () is a suburb of Copenhagen, Denmark, on the east coast of Amager in Tårnby Municipality. It is the site of Copenhagen Airport. In Danish, the airport is often called ''Kastrup Lufthavn'' (Kastrup Airport) or ''Københavns Lufthavn, Kast ...
has long been the busiest airport in Scandinavia but has suffered from an acute shortage of space and its proximity to built-up areas. In 1965, the
Nordic Council
The Nordic Council is the official body for formal inter-parliamentary Nordic cooperation among the Nordic countries. Formed in 1952, it has 87 representatives from Denmark, Finland, Iceland, Norway, and Sweden as well as from the autonomo ...
agreed in principle to build a new international airport on Saltholm, to replace the airport at Kastrup, and to construct a bridge-and-tunnel link across the island to connect Copenhagen and Malmö. The proposal was strongly supported by
Scandinavian Airlines System
The Scandinavian Airlines System (SAS), commonly known as Scandinavian Airlines, is the Flag carrier, national airline of Denmark, Norway, and Sweden. It is part of SAS Group and is headquartered in Solna Municipality, Solna, Sweden.
Including ...
, the main user of Copenhagen Airport. The plan envisaged building two pairs of runways, which would carry up to 20 million passengers a year by 1990. A bridge would connect it to Malmö and a tunnel would link to Kastrup on the Danish side. The project was costed at the equivalent of £250 million in 1967 (£3.1 billion / €3.4 billion at 2009 prices).
The plan was approved by the Danish parliament in 1969 with completion scheduled for 1985. However, it was repeatedly delayed; contributory factors included the
1973 oil crisis
In October 1973, the Organization of Arab Petroleum Exporting Countries (OAPEC) announced that it was implementing a total oil embargo against countries that had supported Israel at any point during the 1973 Yom Kippur War, which began after Eg ...
and its economic fallout, a slump in air travel, and opposition from campaigners concerned about the impact on the fragile environment in the Øresund and around the island. The plan was abandoned in 1979 and further investment was made in
Copenhagen Airport
Copenhagen Airport, Kastrup (, ) is an international airport serving Copenhagen, the capital of Denmark, as well as the wider Øresund Region, including Zealand and the southern Sweden, Swedish province of Scania. In 2023 it was the largest ai ...
instead.
[Jim Berry, Stanley McGreal, ''European Cities, Planning Systems and Property Markets'', p. 166. Taylor & Francis, 1995. ] When the
Øresund fixed link was eventually built in the 1990s, it was routed 1 km south of Saltholm to avoid damaging the island and the surrounding shallow waters.
See also
*
List of Danish islands
References
Further reading
* Niels Houkjær: ''Saltholm'' in ''De danske øer - En lystrejse til Danmarks småøer'', S. 151 ff., Nordisk Forlag A/S, Kopenhagen 2006,
{{Denmark islands
Islands of Denmark
Important Bird Areas of Denmark
Important Bird Areas of Baltic islands
TÃ¥rnby Municipality
Øresund Bridge
Geography of Copenhagen
Øresund