I don't want to pick nits, but this statement is misleading and is not really correct. The War College which is in Pennsylvania is the Army's War College. It is attended primarily, but not exclusively, by senior Army officers. The Air Force has a War College too, and it is in Alabama, attended primarily by senior Air Force officers. The Navy also has one, which, if I recall correctly, is in Rhode Island, attended primarily by Navy officers. Then there is the National War College in Washington DC, which all services utilize, and is generally considered to be the gold standard of senior service schools. There is yet another senior service school, the Industrial College of the Armed Forces, but it is another story altogether.
While it is well nigh impossible to be selected for flag rank without having attended one of the senior service schools, it is not at all accurate to state that all flag officers have attended the Army's War College.
For what it's worth.
John
There are also major curricula out in Kansas.