Thread by @pptsapper

Right now, 100 years ago, Col. George C Marshall was staring at a map very much like the one below, save that he had no idea how far the massed US Army divisions would advance. It was the eve of America's largest battle: the Meuse-Argonne Offensive. And Marshall had planned it.

https://twitter.com/Erikhistorian/status/1042617298618667009

From the Aisne River to the Meuse River stood the largest US Army ever assembled in our history to that point. Fifteen divisions - 28k men each, twice the size of French & German divisions - stacked up, waiting for the word to go. Some were veterans. Most were very, very green.

Over 30 French divisions are stacked up to their left and right. The Americans, with 1.2 million troops now in France, have their own front. But it's a hell of a front: the Argonne Forest. Already a natural obstacle, it has been held by the Germans for 4 years. It is a fortress.

The Argonne doesn't just exist, it looms. I was there this summer and you never wonder if you're seeing it. It is massive, dark, and foreboding. And that's without the lines of trenches, rolls of barbed wire, steel-reinforced pillboxes, & underground bunkers.

Right about now, 100 years ago, gun crews for 2,700 pieces of Allied artillery would be making their final checks to their pieces; counting the shells mounding in graceful piles behind the guns; officers and NCOs running over the scheme of fire one last time.
#WW1 #MeuseArgonne

In the trenches, platoon leaders were reviewing the plans with their commanders or on last minute recons to check the wire. Their maps would only contain the enemy's information rather than friendly - for fear of being captured. In the 9 US attack divisions, there were 1,728 PLTs

Sergeants in the 6,912 squads made sure their men were resting - or appearing to rest. Last minute preparations were made. A Stokes mortar moved here, a 37mm gun brought up there. Cooks readied coffee for the men in the morning. Those who could, slept.

In order to keep the Germans from discovering the battery placements of the 28th Division's artillery in the forests, they didn't fell trees. Rather, they tied the tops together with wire & cut thru the trunks. One stroke of an axe would cut the wire, bringing the trees down.

At 0230 on September 26, the cables were cut, the trees fell, revealing the guns of the 28th "Keystone" Division; which opened fire at once, joining the 2,700-gun chorus of destruction that was ranging from the Argonne Forest to the Meuse River.

For three hours, the sleek 75mm guns, the stubby 155mm howitzers, the railway guns, the 155mm GPFs, barked, shook, rattled, heaved, and smoked, firing more munitions than had been fired in the entire four year period of the American Civil War.
#MeuseArgonne

At 0530, the ground covered in a dense fog, the barrage shifted, its nature changing from protective rather than offensive, as it rolled slowly forward. Behind it came the infantrymen of 9 divisions, out into the shell-pocked, ravine-rutted, wire-filled No-man's-land.

The dense fog and nature of the ground played hell with unit cohesion, liaison between right and left units, and communication to the rear. Fierce combat began to clean out trenches, pillboxes, and dugouts. Conflict swirled around the base of the tall hill of Montfaucon.

Like Montsec in the St Mihiel Salient, Montfaucon was a formidable height, dominating the surrounding countryside, riddled with bunkers, pillboxes, and trenches. Unlike Montsec, the Germans did not abandon it but stayed to fight. The 79th & 37th Divisions converged on this hill.

The 79th, a National Army division, attacked head-on, receiving fearful losses from German machine gun fire. They would not reach Montfaucon until 1800 that day. Attacking with tanks but without artillery support, they made a lodgement on the slopes of the hill at nightfall.

The 37th "Buckeye" Division of the @OHNationalGuard was a more veteran division. They took their first lines of trenches, seized the Bois de Montfaucon, & kept on going, lapping around the edge of the hill. Patrols from the 37th went up Montfaucon but could not gain the summit

American divisions surged forward, with the goal to create small salients in German lines in order to be able to attack out of them into German flanks. With surprise & speed on their side, they advanced quickly on the 1st day. But German reserve divisions began to flow in.

Barrage map for the 79th Division artillery for Montfaucon, courtesy @OsherMaps. Note the timelines for shifting the barrage forward. Timed with the infantry advance.