This Day in American Military History

26 September 1918: The Battle of Meuse-Argonne began a French-American effort that was part of the Hundred Days Offensive. After four weeks, U.S. troops had advanced ten miles, and the French twenty—but that was enough to rid the Argonne Forest of enemy forces. Meuse-Argonne is considered the final great battle of World War I—it was also one of the costliest in terms of casualties for the United States.

Brandus, Paul. This Day in U.S. Military History (p. 233). Bernan Press. Kindle Edition.