Sarpsborg (pronounced [ˈsɑ̀ʂbɔr] or [ˈsɑ̀rpsbɔrɡ]), historically Borg, is a city and municipality in Østfold county, Norway.

Sarpsborg is part of the fifth largest urban area in Norway when paired with neighbouring Fredrikstad.

Later the genitive case of the name of the waterfall Sarpr (Sarp Falls) was added, it's unclear how Sarpsborg received this part of its name, two interpretations are the most prevalent.

The bear was introduced as early as some time in the 13th century, by the earl of Sarpsborg (Comes de Saresburgh), Alv Erlingsson.

[citation needed] The castle symbolises the fortress (borg) that gave the city its original name.

[7] The city was founded as Borg by the Viking King Olav Haraldsson (Saint Olaf) in 1016.

In modern times Sarpsborg has moved away from being a city based on the local manufacturing and refining industry, with only around ten percent employed within the local manufacturing industry, coinciding with Norway's general shift towards a post-industrial society.

In football, Sarpsborg 08 FF has taken over the local throne, currently playing at the highest national level.