The development of the region has progressed so far that Fredrikstad/Sarpsborg now is considered one urban area. Fredrikstad/Sarpsborg is Norway's seventh largest urban area, with a population of 101,698 as of January 2009[update], of which 42,803 reside in Sarpsborg and 58,895 reside in Fredrikstad.
- "Urban settlements. Population and area, by municipality". Statistics Norway. 2009-06-16. Retrieved 2010-07-12.