Key Facts
- Duration
- ~10 days, March 1945
- Front width
- 75 kilometres (47 miles)
- Armies involved (Allied)
- U.S. Seventh, Third, and French First Armies
- Objective
- Clear Saar-Palatinate; establish Rhine bridgeheads Mainz–Mannheim
- Army Groups involved
- U.S. Sixth and Twelfth Army Groups
Strategic Narrative Overview
Three Allied corps attacked abreast along a 75-kilometre front from Saarbrücken southeast to Hagenau in March 1945. The U.S. Seventh Army drove up the Kaiserslautern corridor as its main effort, while the French First Army cleared a narrow Rhine strip into northeastern Alsace. The U.S. Third Army conducted diversionary attacks across the Moselle, protecting the Sixth Army Group's left flank and critically overrunning German lines of communication, accelerating the collapse of Wehrmacht resistance.
01 / The Origins
By early 1945, Allied forces were advancing toward Germany's western frontiers. Supreme Allied Commander General Dwight D. Eisenhower sought to clear the Saar-Palatinate region and secure bridgeheads over the Rhine between Mainz and Mannheim. The operation was designed to coordinate three Allied armies across two army groups, eliminating German Army Group G from a strategic corridor and positioning Allied forces for a full crossing of the Rhine along its entire German length.
03 / The Outcome
Within ten days, Operation Undertone cleared Wehrmacht defenses across the Saar-Palatinate and pushed Allied forces to the Rhine near Karlsruhe. Combined with the Third Army's rapid advance, the operation completed Allied occupation of the Rhine's entire west bank within Germany. German Army Group G under SS General Paul Hausser was unable to hold its lines, and the way was opened for Allied crossings of the Rhine in force.
Belligerents & Mobilization Analysis
Side A
3 belligerents
Jacob L. Devers, Dwight D. Eisenhower.
Side B
1 belligerent
Paul Hausser.