Halden

Formerly  Fredrikshald,   town, Østfold fylke (county), southeastern Norway. It lies along Idde Fjord, which forms part of the border between Norway and Sweden, at the mouth of the Tistedalselva (river). The site was settled in ancient times, and the modern town, founded in 1661, was known as Fredrikshald from 1665 to 1928. Its 17th-century Fredriksten Fort was a strategic border stronghold that withstood many attacks