Sundsvall, town and seaport in Västernorrland län (county), northern Sweden. It lies at the mouth of the Selånger River on the Gulf of Bothnia. It was chartered in 1624 by Gustavus II Adolphus. In 1721 it was burned by the Russians and in 1803 and 1888 it suffered further disastrous fires. The town centre, therefore, dates largely from the 1890s, when it was entirely rebuilt in brick and stone. Lying between Ljungan and Indalsälven, two streams once used for timber floating, Sundsvall is the centre of one of the most important pulp- and paper-producing regions in northern Europe. It also has aluminum and engineering plants. Mid Sweden University has a branch in Sundsvall. Pop. (2005 est.) mun., 94,044.