Recently I ran into an argument about whether the trans-Mississippi had any military value. As a counter I surveyed the 1860 US Census and took the value of bar, sheet and railroad iron produced as an indicator of heavy industry. The result for the Confederacy was:
Figure 1: Breakdown of CSA (not including border states) heavy industry
This only reflects heavy industry. If all manufactures (which include such goods as liquor and cider) are measured then by value the CSA breaks down as follows:
Figure 2: Manufacturing output of the CSA by state
This shows the disparity between the rich trading states of the coasts (and Tennessee, which could access the coast using the river) and the rest. However, this is small potatoes compared to the whole US:
Figure 3: Manufacturing output of the US, 1860.
It shows just what the border states were worth, they would have doubled the CSA manufacturing output. In heavy industry they would more than double the percentage and a CSA including the border states has a clear third of the combined US heavy industry. As it stands the CSA had 15% of the heavy industry and the border states had 17%. US heavy industry is dominated by four states; Ohio (17%), Massachusetts (16%), New York (13%) and New Jersey (10%). The first two have more heavy industry than the whole CSA. Virginia in the Union also had a 10% share of heavy industry, equal to New Jersey.
My point being an agreement with Brian Holden Reid (America's Civil War: The Operational Battlefield 1861-3, pg 130); Virginia was by far the most important state of the Confederacy and that the focus on defending it was fully justified. The Mississippi theatre mattered little to the Confederacy's military power.