Porsgrunn is a municipality in Telemark county, Norway. It is located in the traditional district of Grenland. The administrative centre of the municipality is the city of Porsgrunn. Some other notable settlements in Porsgrunn include the town of Brevik and the villages of Langangen and Heistad.

The 164-square-kilometre (63 sq mi) municipality is the 315th largest by area out of the 356 municipalities in Norway. Porsgrunn is the 29th most populous municipality in Norway with a population of 37,056. The municipality's population density is 230.5 inhabitants per square kilometre (597/sq mi) and its population has increased by 4.7% over the previous 10-year period. The conurbation of the cities of Porsgrunn and Skien is called Porsgrunn/Skien by Statistics Norway and it is considered to be the seventh-largest urban area in Norway.

The town of Porsgrunn was established as a municipality on 1 January 1838 (see formannskapsdistrikt law). The small urban town of Porsgrunn grew over time. On 1 July 1920, the growing town annexed some adjacent areas of some of the neighboring rural municipalities: an area of Gjerpen Municipality (population: 437), an area of Eidanger Municipality (population: 550), and an area of Solum Municipality (population: 1,614).

During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee. On 1 January 1964, there was a major municipal merger where the following areas were merged to form a new Porsgrunn Municipality.

• the town of Porsgrunn (population: 10,863)
• the town of Brevik (population: 2,498)
• all of Eidanger Municipality (population: 13,018)
• the Bakke area (population: 75) of Hedrum Municipality in Vestfold county
• the Enigheten, Høyberg, and Skavåsen areas (population: 12) of Brunlanes Municipality in Vestfold county

On 1 January 1968, an area of Skien Municipality (population: 3,554) was transferred to Porsgrunn Municipality (these areas had originally been part of Solum and Gjerpen municipalities).

The place is first mentioned in existing historical records in 1576 ("Porsgrund") by the writer Peder Claussøn Friis in his work Concerning the Kingdom of Norway (see the article: Norwegian literature). He writes: "Two and a half miles from the sea, the Skien River flows into the fjord, and that place is called Porsgrund." The name was probably given during medieval times to the then swampy area by the nuns of Gimsøy Abbey, who went here to collect the shrub pors ("Bog Myrtle"). The last element of the name grunn which means "ground". The name was historically spelled Porsgrund. On 1 January 1930, the spelling of the name of the municipality was changed to Porsgrunn, giving it a more "Norwegianized" spelling.

The coat of arms was originally granted on 16 January 1905 for the town of Porsgrunn. The arms were originally devised in 1905 when the city needed a new city hall. After the municipal merger on 1 January 1964, the old arms were re-adopted by the new, larger Porsgrunn Municipality. The blazon is "Gules and azure, a bend between a bog myrtle branch and an anchor argent" (Norwegian: Delt av sølv skråbjelke. Øvre felt i rødt en sølv pors-kvist, nedre felt i blått et sølv anker). This means the arms have a red (above) and blue (below) field (background) and the charge is a diagonal bend (stripe) with an anchor below it and the branch of a bog myrtle plant above it. The charge has a tincture of argent which means it is commonly colored white, but if it is made out of metal, then silver is used. The silver bend (stripe) symbolizes the small river running through the city. The bog myrtle plant is a canting symbol since the name Porsgrunn comes from the Norwegian word for the plant. The anchor on a blue background symbolizes the importance of the local harbor and sea. The arms were designed by Wilhelm Rudolph.

The Church of Norway has two parishes (sokn) within the municipality of Porsgrunn. It is part of the Skien prosti (deanery) in the Diocese of Agder og Telemark.

Churches in Porsgrunn

Parish (sokn)	Church name	Location of the church	Year built
Eidanger	Brevik Church	Brevik	1963
	Eidanger Church	Eidanger	c. 1150
	Herøya Church	Porsgrunn	1957
	Langangen Church	Langangen	1891
	Stridsklev Church	Porsgrunn	2000
Porsgrunn	Vestre Porsgrunn Church	Porsgrunn	1758
	Østre Porsgrunn Church	Porsgrunn	2019

Porsgrunn has been an important harbor town in the Grenland area since the late 16th century. In 1653, the Customs House was moved further down the Skien river from Skien to Porsgrunn mainly because industrial waste such as sawdust and mud made the river too shallow to allow boats to go any further up the river. Moving the Custom House to Porsgrunn added to the flourishing harbor activity and Porsgrunn became a thriving market town with a ladested status.

In the 18th century, Porsgrunn was the home of some of Norway's most influential families at the time, such as the Aalls, Cappelens, Løvenskiolds, and Deichmans. Also in this period, Porsgrunn was considered the cultural centre of Norway. The city was granted limited city status as a kjøpstad in 1807. The town was established as a municipality on 1 January 1838, and it was expanded to full city status in 1842.

Porsgrunn was once home to Skomvær, the country's largest sailing ship. In 1985, the sculpture Amphitrite, the wave and the sea birds was unveiled in Porsgrunn. The sculpture, which is one of Jørleif Uthaug's best known works, has a nautical theme in honor of Porsgrunn's maritime history.

Porsgrunn Municipality borders the municipalities of Skien and Siljan to the north, Bamble in the west, and Larvik in the east. It is part of a cluster of municipalities in southern Telemark that constitute the Grenland area of Norway. The Frierfjorden, Gunnekleivfjorden, and the mouth of the river Telemarksvassdraget or Porsgrunn River (Porsgrunnselva) are located in the western part of the municipality. The peninsula of Herøya, southeast of the main city centre, was originally an industrial park and has grown into a suburb of Porsgrunn. The Eidangerfjorden runs through the central part of the municipality.

Porsgrunn Municipality is responsible for primary education (through 10th grade), outpatient health services, senior citizen services, welfare and other social services, zoning, economic development, and municipal roads and utilities. The municipality is governed by a municipal council of directly elected representatives. The mayor is indirectly elected by a vote of the municipal council. The municipality is under the jurisdiction of the Telemark District Court and the Agder Court of Appeal.

The municipal council (Kommunestyre) of Porsgrunn is made up of 49 representatives that are elected to four year terms. The tables below show the current and historical composition of the council by political party.

This list is incomplete; you can help by adding missing items. (October 2023)

The mayors (Norwegian: ordfører) of Porsgrunn (incomplete list):

Porsgrunn is an important center of industry and has a long history of heavy industry. Important industries in Porsgrunn include:

Transportation links from Porsgrunn:

• Bus (Oslo, Kristiansand, Notodden)
• Train (stops at Porsgrunn Station)
  • The Vestfold Line to Drammen Station and onwards to Oslo Central Station
  • The Bratsberg Line to Skien Station and Notodden Station
• Ferry (Fjordbåtene i Brevik)

• Cort Adeler (1622–1675), a Norwegian/Danish admiral
• Niels Aall (1769–1854), an estate owner, businessman and politician who built Ulefos Manor
• Severin Løvenskiold (1777–1856), a nobleman, politician, and Prime Minister of Norway 1828/1841
• Thobias Petter Wiibe (1815–1891), a politician and Mayor of Porsgrund in the 1850s
• Niels Mathiesen (1829–1900), a politician, merchant, and Mayor of Porsgrund during the 1860s to 1880s
• Jørgen Christian Knudsen (1843–1922), a ship-owner and politician
• Johan Castberg (1862–1926), a politician and government minister during the 1900s & 1910s
• Carl P. Wright (1893–1961), a politician who was Mayor of Porsgrunn during the 1930s
• Erik Hesselberg (1914–1972), a sailor, author, painter, sculptor, and Kon-Tiki crewmember
• Einar Tufte-Johnsen (1915–1985), an aviation officer and head of NATO Defense College
• Finn Kristensen (born 1936), an electrician, trade unionist, and government minister during the 1980s & 1990s
• Ann-Marit Sæbønes (born 1945), a physiotherapist and first female Mayor of Oslo during 1992-1995
• Mads Gilbert (born 1947), a physician, humanitarian, activist, and politician
• Kristin Halvorsen (born 1960), the former leader of Socialist Left Party and a government minister
• Vibeke Hein Bæra (born 1964), a lawyer, defended Anders Behring Breivik at his trial
• Robin Kåss (born 1977), a politician who was elected Mayor of Porsgrunn in 2015 & 2019
• Torbjørn Røe Isaksen (born 1978), the former leader of Norwegian Young Conservatives and the Minister of Education and Research
• brothers Kjetil Aleksander Lie (born 1980) & Espen Lie (born 1984), chess players

• Hans Eleonardus Møller Sr. (1780–1860), a businessperson
• Jørgen Wright Cappelen (1805–1878), a bookseller and publisher who co-founded Cappelen Damm
• Johan Jeremiassen (1843–1889), an entrepreneur, ship-owner, consul, and politician who founded the porcelain flatware company Porsgrund Porselænsfabrik
• Petter Stordalen (born 1962), a billionaire businessman, real estate developer, and hotel owner

• Halfdan Christensen (1873–1950), a stage actor and theatre director
• Tone Schwarzott (born 1941), an actress and poet
• Yngvar Numme (born 1944), a singer, actor, revue writer, and director
• Bugge Wesseltoft (born 1964), a jazz musician, pianist, composer, and producer
• Stephen Ackles (born 1966), a vocalist, pianist, and songwriter
• Øyvind Torvund (born 1976), a composer
• Aleksander Walmann (born 1986), a singer for Norway in the Eurovision Song Contest 2017
• Didrik Solli-Tangen (born 1987), a singer for Norway in the Eurovision Song Contest 2010
• Emil Solli-Tangen (born 1990), a opera singer

• Jørgen Juve (1906–1983), a football player, jurist, journalist, and non-fiction writer who was the highest scoring player for Norway with 33 goals in 45 games; captain of Norway, which won Olympic bronze medals in the 1936 Summer Olympics
• Cathrine Roll-Matthiesen (born 1967), a former handball player and team silver medallist at the 1988 & 1992 Summer Olympics
• sisters Anita Valen (born 1968) & Monica Valvik (born 1970), racing cyclists who won the Norwegian National Road Race Championships eleven times between them
• Ronny Deila (born 1975), a football manager who was head coach of New York City FC and former player with 352 club caps
• Tony Capaldi (born 1981), a professional footballer with nearly 300 club caps
• Rune Jarstein (born 1984), a football goalkeeper with about 400 club caps and 69 for Norway
• Espen Ruud (born 1984), a football defender with 430 club caps and 35 for Norway
• Fredrik Nordkvelle (born 1985), a footballer with 360 club caps

Porsgrunn is twinned with:

• Kisumu, Kenya
• Pori, Finland
• Sigtuna, Sweden
• Sønderborg, Denmark
• Sundsvall, Sweden

• Municipal fact sheet from Statistics Norway (in Norwegian)
• Telemark travel guide from Wikivoyage
• Porsgrunn travel guide from Wikivoyage
• Municipal website (in Norwegian)
• Porsgrunds Porselænsfabrik AS (porcelain factory) (in Norwegian)
• www.isola.com (in Norwegian)
• Porsgrunn public library (in Norwegian)