It doesn't look like this has been proposed in this board since 2013 so it might be worth floating, although nobody has asked for one so it might not be. Nonetheless:
A lot of posts in Off-Topic are about geography or geography-adjacent topics (area codes, time zones, metro areas, population, town names, to name a few recent examples) and there is a significant overlap on this forum between people who are interested in both roads and people who are interested in geography, given the close nature of the two subjects. Establishing a geography board for these reasons follows the logic of the Urban Planning and Design board which so far has been welcome, although it is not the most active board. I feel it would also help more with sorting out more serious discussion from the fluff threads that are frequently posted in Off-Topic (not that I have a problem with those).
Even still, there are others such as Bridges, which are even more underutilized. Geography-related topics seem to be brought up much more frequently than topics which would go in either of those boards.