The 'Hitler-Riegel' was a German defence line in Italy (November 1943/May 1944).

The construction of this 26-mile (42-km) line was ordered by Adolf Hitler as a back-up for the 'Bernhardt-Linie' defences and as part of the fixed defences for the Liri river valley. The 'Hitler-Riegel' defences extended from a western end at Terracina on Italy’s Tyrrhenian Sea coast to an eastern end near Monte Cairo at Melfa Atina in the Apennine mountains via Fondi, the Aurunci mountains, Pontecorvo and Piedimonte.

In January 1944, as its continued integrity was threatened by Allied pressure, the line was reallocated the name 'Senger-Linie' to avoid any possibility of the Führer’s name being associated with a defeat. To the Allies the 'Hitler-Riegel', 'Bernhardt-Linie' and 'Gustav-Linie' were collectively known as the Winter Line defences.