A map-based alternate history cliché occuring due to timeline writers' and especially mapmakers' laziness. The gist is that a global or regional map of an alternate history universe features the world (or nation/area/region) being divided into several big random empires, 1984-style.
Years ago, Imajin coined the term “space filling empire” for this phenomenon. (However, it had been a commonly pointed-out annoyance even before that.)
A variant of this cliché is the Space-Filling Union: An irrational unification of random African or Asian states, just because they happen to lie near each other.
As it seems that nobody ever researches Africa, and indeed nobody even cares about what happens there, AH maps including Africa often show the continent divided between around three to six empires, or at least having one or two of those superstates, especially in the Sahara and Sahel.
Another area particularly prone to Space-Filling Empires is Central Asia - see the That Damned Kazakh Border page for more info.
A common “Space-Filling Union” example, particularly in badly thought-out future history works, is the unification of China and India, completely ignoring their massive territorial disputes and geopolitical rivalries of the two countries. Bonus points if the unification occurs completely out of the blue, as if it was a complete piece of cake from a political, diplomatic or logistical standpoint.
As a reference to this cliché and a pun on its name, Thande's Look to the West timeline includes an actual colonial territory with the nickname of Space-Filling Empire. In case you don't get the joke: The colony was founded by a certain Mr. Space and Mr. Filling.