The Frieslandriegel, also known as the Assener Stellungen, was a German defensive line established in 1944, spanning from Zwolle to Delfzijl in the Dutch provinces of Overijssel, Drenthe, and Groningen. Its construction was prompted by the Allied invasion of Normandy in June 1944. On 30 August 1944, German authorities decided to reactivate the Westwall, a defensive line stretching from the Swiss border to Kleve. To prevent the Allies from bypassing this line via the Netherlands, it was extended northward to the sea. For this purpose, the previous Dutch IJssel Line was reused and a completely new line was constructed: the Frieslandriegel.

Due to the Allies' rapid advance, the Frieslandriegel had to be built quickly. It consisted of a tank ditch, trenches, and machine gun posts, but lacked large bunkers due to time and material constraints. Instead, smaller one-man bunkers were scattered along the line. After the war, most of the positions were cleaned up, but remnants still exist, particularly in nature reserves.

One notable site is the Baggelhuizen nature reserve in Assen, where many remnants of the Frieslandriegel remain. These include a substantial section of a V-shaped tank ditch, as well as traces of trenches, foxholes, and small concrete structures.