If you haven't checked out my interactive D3FB Map yet, do yourself a favor and go mess around with it for a while. What I've done is plotted every D3 team since 1999 on one bubble map, with the bubbles nearly* proportional in size to their average rating over that time frame.
While I was building the map, I decided to do some fun little research into the geography of Division III football, such as the teams on the extents of the compass:
-- North: Whitworth
-- South: Trinity Texas (interestingly, Sewanee, the so-called University of the South, is only the thirtieth most Southern DIII school that plays football)
-- East: Husson
-- West: Linfield
I also checked which teams are the furthest-removed from the rest of the division, which was obviously dominated by teams in the NWC, SCIAC, SCAC, and ASC. Outside of those schools, some teams in the far Northeast (Husson, Maine Maritime, Massachusetts Maritime), Midwest (Concordia-Moorhead, Minnesota-Morris), and South (Millsaps, Huntingdon) were high on the list. The teams closest to the geographic center of the division happen to be Bluffton and Ohio Northern. In case you're curious, the geographic center happens to be this guy's farm:
Which is pretty much in the middle of nowhere in Northwest Ohio. As is the "Talent Center," which is what I'm calling the point on the globe that would minimize the travel distance to each D3 football program, with distances weighted by the team's average rating from 1999-2015 (so teams with a low rating will matter less in the calculation).
The "Talent Center" of Division III appears to be a lumber mill about an hour Northeast of Fort Wayne in Indiana, near Baldwin Wallace.
The highest concentration of teams in general appears to be in the Pennsylvania / New Jersey / Delware / Maryland area, where schools such as Wesley, Rowan, Widener, Delaware Valley, Muhlenberg, and Johns Hopkins reside. Upstate New York, the Western shore of Lake Michigan (from Chicago to Green Bay), and Ohio also have a pretty high concentration of schools also.
Other things I was pleased to discover:
Centre is pretty much centered in Kentucky
If you, like me, think the Upper Peninsula of Michigan looks like a fish, then Finlandia is situated on one of its fins.
Because of the way this map projection generalizes shorelines, Puget Sound is actually inside of Puget Sound
*I say nearly proportional because I added 0.25 to every team's rating. If I hadn't, the bubbles for Finlandia, Maranatha Baptist, Principia, Blackburn, etc. would have been less than one pixel wide.