Halden is a town and municipality in the province of Østfold in Viken county in eastern Norway. The large municipality of Halden borders Rakkestad in the north, Aremark in the east, and Sarpsborg in the northwest, as well as the municipalities of Strömstad, Tanum and Dals-Ed in Sweden in the southwest, south and southeast, respectively.

The municipality consists of the former districts Berg and Idd as well as the urban municipality Halden. Berg and Idd are typical agricultural areas, while Halden is one of Norway's oldest industrial cities. The industry gained power from waterfalls in the river Tista, which forms the lower part of the Halden watercourse.

Halden is Norway's border town with Sweden and is characterized, historically and visually, by Fredriksten Fortress.


Throughout the municipality, the bedrock of bedrock origin, granite along the Iddefjord south of the city center, is mainly gneiss elsewhere in the municipality. The bedrock has a clear stretching direction northwest – southeast along the Iddefjord and a number of valleys and watercourses are characterized by this. Otherwise, there are cracks across the direction of the area, including the Ringdalsfjord, the outer part of the Iddefjord, and its extension to the east with Tistedalen and Femsjøen.

The Quaternary geology is characterized by the large ridge that runs through the municipality from northwest to southeast and is particularly evident at Rokke.

Watercourses and rivers
Further south, the row dams up several large lakes, including Lake Femsjøen. Tista - below Femsjøen - and Steinselva - above Femsjøen - form the lower course of the Halden watercourse, known for its canal facilities and locks. The Enningdalsvassdraget flows to the bottom of the Iddefjord, partly also through Sweden. In the east and south there are large stretches of forest. To the northwest and on Iddesletta just southeast of the city center are the most important agricultural areas, both places outside the row.

Tista has waterfalls that laid the foundation for sawmills and industry; the river flows through the old industrial town and former town of Tistedal. Halden's city center is located on both sides of the river which divides the city in two, the north side and the south side. There is a connection between the districts by bridges, in the center there is a footbridge in addition to the ordinary bridge.

Meteorological measurements have been conducted under the auspices of met.no in Halden from 1884. The highest and lowest officially registered temperatures in the municipality are 32.0 degrees on 8 August 1975 at Prestebakke and −33.7 degrees on 15 January 1893 at Krappeto, respectively.