“About 35% of the time, the institutions found in the officers’ backgrounds were either VMI or the University of Virginia. When the other Virginia schools are added in, the sample rises to 48%......it appears that Lee’s regimental command was about one half Virginia educated.”
“The Army of Robert E. Lee” by Philip Katcher
“Out of some 1763 individuals who served in the rank of Colonel in Lee’s army, only 72 had been professional soldiers before the war, but 157 had attended VMI, 78 West Point, 40 the South Carolina Military Academy, 16 the Georgia Military Academy, 4 the U S Naval Academy, and 1 the Lagrange Military Academy.”
“Two Great Rebel Armies” Richard McMurry
"Douglas S Freeman calculated that in 1861, Virginia could claim 104 living graduates of the U S Military Academy; the other ten Confederate states had a combined total of only 184. In early 1861, an officer from Nashville made a compilation of the 1132 officers then on active duty with the U S Army. He found that 304 of them were from the eleven states that would eventually join the Confederacy. Of these 304, Virginia was credited with 137, South Carolina with 40, and North Carolina with 36-a total of 213 [70.1%] from the 3 eastern Confederate states.
Even before she left the Union, Virginia, with certainly the strongest military tradition of any Southern state, had a fairly well developed militia....Lee, for example, could build his army upon what his greatest biographer, Douglas Southall Freeman, described as a “partly organized” militia….."
“Lee’s Lieutenant’s” and “Robert E Lee: A Biography” both by Douglas S Freeman
Freeman makes several references to Lee’s officer corps and their backgrounds in these two excellent works.