Why was the Siege of Vicksburg a major Union victory? It led to Lincoln's issuing of the Emancipation Proclamation. It stopped the South's northward advancements. It devastated farmlands in the South. It gave the Union complete control of the Mississippi.

Option: It gave the Union complete control of the Mississippi.

Explanation:

The Seige of Vicksburg became a major Union Victory because it allowed the Union to control over the Mississippi River. For the South, the river played a significant role because it was the last port on the river held by the South. Confederate troops supplied goods to Texas, Louisiana, and Arkansas.

By getting victory in Vicksburg, Union closed the trade, fortifications and transportation, eventually weakened the South in the Civil War.