Why was a Union victory at Vicksburg so important for the North? It cut off supplies coming from England. It opened the door for the fall of Richmond. A great moral victory was badly needed. It made taking of the Deep South possible.

The Union victory at Vicksburg was so important for the North because it made taking of the Deep South possible.

Explanation:

The fall of Vicksburg in the hands of the Union meant that the North took full control of the Mississippi River. In this way, the Union cut the Confederate territory into two parts without connection to each other. By controlling the Mississippi, the Union made it impossible to resupply troops and resources from Texas and Louisiana to the rest of the Confederacy. Due to the shortage, the Deep South (Carolina, Mississippi, Alabama, Georgia and Florida) was practically isolated and surrounded by the enemy, with which, without resources or reinforcements, and with Union troops stationed on all flanks, their fall was taking place progressively.