Jakobstad (yäk´ŏŏpstäd´) or Pietarsaari (pē´ĕtärsä´rē), city (1996 pop. 19,905), Western Finland prov., W Finland, on the Gulf of Bothnia. It is an important port and industrial center. More than half the inhabitants speak Swedish. The city was founded in 1652. The Finnish national poet J. L. Runeberg was born (1804) there.