Nations are of course the standard model of political organization since the twentieth century. They are characterized by clearly demarcated boundaries with precise geographical coordinates, and equally clear administrative structures, including internal administrative divisions, such as states, counties, provinces, townships, wards, and the like. While the world's nations have a broad variety of systems of governments, they share a global recognition that they have exclusive governance over a recognized territory.

As of 2010, the United Nations recognizes only 192 nations in the world, but there are a number of problematic territories not included: Taiwan, Kosovo, Palestine, Greenland, Western Saraha England, Scotland, Wales, Vatican City, and so forth. We have tried to not take sides in political disputes, but rather list all political entities that have - for the time being - direct control over their own territory without being dependent in practice upon another polity.

Each nation has a different number of hierarchically related administrative units, as well as using different nomenclature (province vs. state, etc.) even within a given language, while of course many nations use quite different languages to label their administrative unit types. For that reason, we also document herein the individual nations and with their distinctive administrative hierarchical schemes and labels.