FREDRIKSHALD (HALDEN), a seaport of Norway, in Smaalenene amt (Ostfold Fylke) ; 85 miles by rail S. by E. of Oslo. Pop. (193o), 10,278. It is situated on both banks of the Tistedal river at its outflow to the Ide fjord. The town is surrounded by high ground on which is the famous fortress Fred riksten, protected on three sides by precipices, founded by Fred erick III. (1661), and mainly showing, in its present form, the works of Frederick V. (1766) and Christian VII. (1808). Monu ments commemorate the siege of the town in 1718. Fredrikshald is close to the Swedish frontier, and had previously (166o) with stood invasion. Its name was changed from Halden to the present form in 1665 in honour of Frederick III. The town was almost totally destroyed by fire in 1759 and 1826. The castle surrendered to the Swedes in and its capture was followed by the con quest of the kingdom and its union with Sweden. Fredrikshald exports timber and marble is quarried for ornamental work. There are railway communications with all parts of Sweden and coastal services.