I've been working on a history of fencing in my division for quite some time, now. One thing that I noticed are the dynamics of division growth and the creation of new divisions.
For instance, I am in the Gulf Coast Division. It was formed in the immediate post-WWII era (1949) when the old Texas Division split in two (Gulf Coast Division and North Texas Division). From what I can tell so far, fencing reached a combination of critical mass (rapid increase in the numbers of fencers and clubs) and geographic stress. (If you live in Ft. Worth you probably get tired of half the tournaments being in San Antonio or Galveston).
Similarly, the South Texas Division split off from the Gulf Coast Division in 1965. Fencing in the Austin and San Antonio areas was robust and the commute for divisional events to the Houston/Galveston area was unappealing.
I was curious if any of the American fencers on this board have any knowledge of the circumstances and dates when their own divisions formed.
I believe there has been at least one new division in recent years when the Green Mountain Division was formed.