town, southern Norway, at the mouth of the Skienselva (river) on Frierfjorden. Established as a customs post in 1652 with the name Porsgrund, it received its town charter in 1842. An export and industrial centre, it contains the huge Norsk Hydro chemical factories. It is known for producing fertilizers, as well as for its shipyards, oil refinery, metalworks, and lumber mills. Norway's finest porcelain is manufactured there. Tourist sites include the Østre Porsgrunn (1760) and the Vestre Porsgrunn (1758) churches, both of which exemplify the Rococo style in their interior design. Pop. (2007 est.) mun., 33,977.