Because of Union victories at Fort Donaldson and Fort Henry, the outer perimeter of defenses that protected western and middle Tennessee left the city of Memphis, Tennessee exposed to Union attack by river. After Grant's victory at Shiloh the Confederate forces would concentrate their strength along the Ohio and Mobile Railroad in northern Mississippi. The disastrous defeat of General Earl Van Dorn at Corinth, Mississippi left the door wide open for a union victory at Vicksburg and the fall of her sister fortress at Port Hudson, Louisiana. The Mississippi River represents the jugular vein of the South. The capture of New Orleans by Admiral Farrago effectively shut commerce that the South depended upon. The northern strategist fully recognized that the control of the Mississippi and her tributaries would prevent any Southern expansion into Missouri and Kentucky. The 18th Arkansas infantry played a role in the defense of both the upper and lower Mississippi River. This is their story.