Why did the north want to gain control of the Mississippi?

There were two main reasons. First, the Mississippi river was the south's main way of transporting goods. They sent goods down the river to port cities such as New Orleans where the goods were then shipped off and sold. Second, by gaining control of the Mississippi river, the north could successfully divide the south into two separate parts, neither of which could reach each other to assist each other. Gaining control of the Mississippi river was a key part of winning the war for the north.