In spring 1863 the Union forces forced Vicksburg and Port Hudson to surrender, giving them control of the Mississippi and accomplishing the objective of splitting the Confederate forces in two. The Union army forced the Confederates to leave Gettysburg in the North and retreat to Virginia. In East Tennessee, the Battle of Chickamauga, the second bloodiest battle in the Civil War after Gettysburg, took place. Fought between 18 and 20 September, the Union forces were deflected from capturing the city of Chattanooga where they wanted to block the rail gateway to the Deep South. However, subsequent battles in the Chattanooga region, under General Ulysses S. Grant, resulted in Union victories. Meanwhile the Anaconda Plan, a Union naval blockade of Confederate ships in the Atlantic and the Gulf coast, was finally proving effective at blocking weapons and supplies from reaching the South.
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