Seine River Crossing at Mantes-Gassicourt facts for kids

Quick facts for kids Seine River Crossing at Mantes-Gassicourt
Part of Operation Overlord, Battle of Normandy
Date 18–20 August 1944 Location Present Day Mantes-la-Jolie, France 49°0′31″N 1°41′12″E / 49.00861°N 1.68667°E / 49.00861; 1.68667 Result Allied victory
Belligerents
United States	Germany
Commanders and leaders
George Patton Ira T. Wyche Joseph Bacon Fraser	Unknown
Casualties and losses
none	1 tank captured 19 vehicles captured 43 aircraft shot down

The Seine River Crossing at Mantes-Gassicourt was a key event during World War II. It was the first time General Patton's Third Army managed to cross the Seine River in France. This crossing happened right after the huge D-Day landings and helped the Allies move closer to freeing Paris. Over two days, American anti-aircraft guns were very effective, shooting down nearly 50 German planes.

Background to the Crossing

Map showing the breakout from the Normandy beachhead

After the successful invasion of Normandy in June 1944, the U.S. Third Army was formed in France. Its job was to help break out of the Normandy area, an effort called Operation Cobra. The push towards the Seine River began on August 3. General Patton was told to secure the area around the Mayenne River and protect the southern side of the main Allied forces.

Patton's army moved quickly. One part of his army, the XV Corps, headed towards Laval and Le Mans. Another part, the XX Corps, moved south towards Nantes and Angers. This fast movement helped protect the main Allied advance.

Operation Tractable and the Falaise Pocket

The formation of the Falaise Pocket, from 8–17 August 1944

The Third Army's XV Corps drove from Mayenne south to Le Mans. Then, it turned north towards Argentan by August 12, 1944. This was where the Battle of the Falaise Pocket was happening against the German Seventh Army.

The next day, the 5th U.S. Armored Division advanced about 35 miles. They reached positions overlooking Argentan. On August 13, General Bradley stopped Patton's plan for a further push north towards Falaise. Bradley ordered the XV U.S. Corps to "concentrate for operations in another direction." The U.S. troops near Argentan were told to pull back. This decision left a way for German forces to escape from the Falaise Pocket. Patton disagreed but followed the order.

The Drive to the Seine River

While some of the XV Corps stayed near Argentan, other parts of the Third Army continued their advance. Starting on August 15, they began a wider movement towards the Seine River. They cleared a large area north of the Loire River. This advance towards the Seine showed that the "battle of Normandy" was quickly becoming the "Battle of Western France."

Crossing the Seine

The Allied commanders decided to send some of Patton's forces down the west bank of the Seine. At the same time, they saw a chance to grab a bridgehead on the east bank. This would be a starting point for future operations. So, the XV Corps had two missions. The 5th Armored Division would attack down the west bank. The 79th Infantry Division would set up a bridgehead on the east bank.

General Ira T. Wyche received an urgent call on August 19. He was ordered to cross the Seine that very night. His 79th Division needed to get soldiers onto the east bank right away. They also had to build a bridge for vehicles, tanks, and heavy equipment. The goal was to secure enough land (about four to six miles deep) to protect the crossing points at Mantes from enemy artillery fire.

General Wyche expected little resistance. His 79th Division had only met scattered German groups that day. They had captured 19 vehicles and a Panzer IV tank. They had also received only occasional machine gun fire from across the Seine. The biggest challenge was the river itself. Near Mantes, it was between 500 and 800 feet wide.

Luckily, a nearby dam offered a narrow path to walk across. Also, engineers had assault boats and rafts to move troops and light gear. For the main bridge, Wyche got 700 feet of special bridge sections from the 5th Armored Division.

"Through France; 14 Jun - 29 Aug 1944" poster 1 of 4 of battle movements of the 79th Infantry Division.

On the night of August 19, a heavy rain fell. Men of the 313th Infantry walked across the dam in a single line. Each soldier touched the one in front to avoid falling into the water. At dawn on August 20, the 314th Infantry paddled across the river. At the same time, the division engineers started building the special bridge.

In the afternoon, as soon as the bridge was ready, the 315th Infantry crossed in trucks. By nightfall on August 20, most of the division was on the east bank. This included tanks, artillery, and tank destroyers. The next day, more artillery units from the XV Corps also crossed.

Anti-aircraft Defenses

Seine river crossing commemorative shell casing

Under the command of Colonel Joseph Bacon Fraser, the 23rd Anti-Aircraft Artillery Group quickly set up their guns around the bridge. They arrived just in time. On the first day, they shot down about a dozen enemy planes. In total, they shot down 43 German planes in two days. This was a record for an American anti-aircraft artillery group during World War II.

Aftermath of the Crossing

To make the crossing even better, engineers built a Bailey bridge. This new bridge was opened to traffic on August 23. On the east bank, the 79th Infantry Division did a lot more than just hold the bridgehead. They pushed further, fought off German counterattacks, and blocked highways and ferry routes.

They also showed the Germans how bad their situation was. They captured the Army Group B command post at la Roche-Guyon. This forced the German headquarters troops to flee eastward to Soissons. Once the Allies were on the east side of the Seine, the Free French 2nd Armored Division and the US 4th Infantry Division were able to liberate Paris from Nazi occupation on August 24–25.