Eidanger is a former municipality in Telemark county, Norway. The 136-square-kilometre (53 sq mi) municipality existed from 1838 until its dissolution in 1964. The area is now part of Porsgrunn Municipality. The administrative centre was the village of Eidanger where Eidanger Church is located.^[3]

The municipality of Eidanger included a peninsula between the Eidangerfjorden and the Frierfjorden. Situated between the urban municipalities (towns) of Brevik and Porsgrunn. It also included the more rural areas to the north and east of the Eidangerfjorden. The municipality had excellent natural conditions for building harbours, it became the site of Norsk Hydro's plant at Herøya and the Dalen Portland (now part of the Norcem corporation) concrete factory just outside Brevik. More recently, a major industry in the area is Heistad Fabrikker, which makes products for diabetics. Isola maintains its head office and administration office in Eidanger. Isola has two factories in this area where bitumen-based products and steel roofing tiles are manufactured.^[4]

Eidanger Church (Eidanger kirke) is located in the village of Eidanger and was the main church for the municipality. The church was originally a relatively simple stone church in the Romanesque style, probably built ca. 1150. The church was extended in 1787 and received a new sacristy in 1981. The altarpiece, stained glass and the pulpit is from 1991 and made by Terje Grøstad. The baptismal font is of stone and is from the 1890s. The church has two bells, one from 1720 and one from 1940.^[3][5]

The parish of Eidanger was established as a municipality on 1 January 1838 (see formannskapsdistrikt law). On 1 July 1920, an area of northern Eidanger (population: 550) that was adjacent to the growing town of Porsgrunn was annexed and transferred into the town. During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee. 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.^[6]

• 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

While it existed, this municipality was responsible for primary education (through 10th grade), outpatient health services, senior citizen services, unemployment, social services, zoning, economic development, and municipal roads. During its existence, this municipality was governed by a municipal council of directly elected representatives. The mayor was indirectly elected by a vote of the municipal council.^[8]

• List of former municipalities of Norway