The Battle of Kassel was a four-day struggle between the U.S. Army and the German Army in April 1945 for Kassel, a medium-sized city 140 kilometers northeast of Frankfurt am Main, which also is the second-largest city in Hesse (after Frankfurt). The battle resulted as the U.S. Third Army pushed northeast from the region of Frankfurt and Mainz. The battle opened on April 1, 1945 and ended with an American victory three days later. Opposing the Third Army's 80th Infantry Division were an infantry replacement battalion, some heavy tanks, and anti-aircraft guns. Although the Germans gave battle at Kassel, their army was on the brink of collapse as the Western Allies and the Red Army made deep inroads into Germany. The defense of Kassel did not materially impede the Allied advance, and, one month after the battle ended, Germany was forced to capitulate.