Final answer:
Union victories at Fort Henry, Fort Donelson, Shiloh, and Vicksburg achieved the significant war goal of gaining control over the Mississippi River, splitting the Confederacy, and paving the way for Union dominance and eventual victory in the American Civil War.
Step-by-step explanation:
Union victories at Fort Henry and Fort Donelson, Shiloh, and Vicksburg were pivotal in achieving a major Union war goal during the American Civil War. The success at Vicksburg, in particular, was strategically significant because it granted the Union control over the Mississippi River. Controlling the river meant effectively splitting the Confederacy in two, hindering their ability to communicate and transport supplies this dealt a serious blow to the Southern war effort.
The captures of Fort Henry and Fort Donelson served as the initial breakthroughs into Confederate territory, weakening their frontier. The Battle of Shiloh, while a Union victory, was one of the war's bloodiest and illustrated the tenacity of both sides.
Following these victories, the North continued its efforts, increasingly engaging in total war, and not distinguishing between military and civilian targets. This approach aimed to break the will of the Confederacy and force an end to the war. Major General Ulysses S. Grant, who commanded these successful operations, went on to lead the entire Union war effort, culminating in the surrender of Confederate General Robert E. Lee at Appomattox Court House in 1865.