The Union was under the authority of Abraham Lincoln. Lincoln at first was focused more on keeping the union together. It was not until later on in the war did he decide to have a more abolitionist mindset.
Advantage #1 Of Union
We sure do love making guns and cloths!
The two main military leaders of the Union were Ulysses S. Grant and William Sherman. These men were the primary influence on the battlefield and helped to carry the Union to victory. These men also worked with George Meade and George McClellan.
Advantage #2 Of Union
This will go to our brothers in arms!
I'll grant you the victory
The Union utilized the "Anaconda" military strategy. This approach consisted of surrounding the Confederate states both on land, with men, and on the water, with battleships. After this they would slowly push inwards towards the Confederacy and squeeze them in on themselves, just as an anaconda would constrict its prey before consuming it.
Advantage #3 Of Union
GLORIOUS BANK RESERVES!
The Union had access to around 90% of the nation's factories. This allowed them to make weapons and clothing for all the soldiers fighting under the Union, women typically worked in these factories while their husbands were at war. This provided both supplies for the cause and jobs for the people not involved with the front lines.
The Union also had access to 72% of the nation's railroad tracks. This allowed all the supplies to be transported to the front lines. The tracks aided in not only carrying supplies to soldiers but also to moving soldiers from point A to point B more efficiently.
The Confederacy split off from the united States, because of this the Union still had access to the nation's finances such as the national treasury and bank reserves. This gave the Union a much more expansive budget than the Confederacy.