The Battle of Château-Thierry of 3-4 June 1918 was part of the Allied response to the German Aisne offensive of 27 May-7 June 1918 (First World War). That offensive had seen the Germans advance thirteen miles on the first day, the largest single day advance since 1914. Over the next few days the Germans had reached the Marne at Château-Thierry, thirty seven miles from Paris.
Although General John Pershing, the commander of the American expeditionary force in France was committed to the idea of concentrating his troops in a single army, in the crisis caused by the German offensives he agreed to the deployment of the 2nd and 3rd American Divisions. The 3rd Division was sent to Château-Thierry to defend the bridges over the Marne.
The Americans reached Château-Thierry on 1 June and held off the final German attacks of the Aisne offensive. Having protected the bridges at Château-Thierry, the American 3rd Division then took part in a counter-attack against German forces that had crossed the Marne further east, at Jaulgonne. On 3-4 June the Americans, supported by a number of French troops, pushed the Germans back across the river.
The battle of Château Thierry was the second American victory of the war, coming only three days after the first, at Cantigny on 28 May. A further success would follow at Belleau Wood later in June. These early American successes played an important role in the eventual Allied victory as the seemingly endless stream of fresh American troops began to destroy German morale.