The 'Westwall' (iii) was a German extension to the 'Siegfried-Linie' defences ordered by Adolf Hitler in an unnumbered Führerweisung (24 August 1944).

The decision to extend the 'Siegfried-Linie' defences was spurred by the pace and width of the Allied advance toward Germany, for on 20 August the Allies had poured over the Seine river and, one day after the issue of the Führerweisung, took Paris.

By this time Hitler was placing greater reliance on the Nazi party than the army, and the order was therefore sent to the party organisation for the construction of a new 'German defensive position in the west' and the call-up of the civil population in four sectors, that between the Scheldt river and Aachen being the responsibility of Gauleiter Josef Grohé, the Reichskommissar of Belgium and northern France (on 7 September an amendment allocated responsibility to Dr Arthur Seyss-Inquardt, the Reichskommissar of the Netherlands, for the Dutch section from Maastricht to Aachen), that on the Mosel river as far to the south as the boundary of Gau Moselland and Gau Westmark of Gauleiter Gustav Simon, that between the Gau Moselland/Gau Westmark boundary and Saaralben of Gauleiter Josef Bürkel, and that between Saaralben and Belfort of Gauleiter Adolf Wagner.

Though primary responsibility for the 'Westwall' (iii) was thus given to the party, the army was called upon to decide matters of tactical siting, the comparative importance of different sectors and the type of materials to be used. Hitler called for existing fortifications (notably the Ligne Maginot) to be included in the new line wherever possible, and also ordained that the line should consist of defences in depth, with an uninterrupted anti-tank obstacle and clear fields of fire in front of it.

On 29 August Hitler ordered a comparable line to be built along the North Sea coast between Denmark and the Netherlands; and the 1 September order modified the party control of various sectors of the 'Westwall' (iii) without altering the substance of the preparations ordered on 24 August.