What are the 7 political regions of the US?

There are two answers to this question, depending on which "America" you are referring to.

In the general common English meaning, "America" means specifically the United States of America. This nation is composed of several types of entities: states, territories, autonomous regions governed under U.N. mandate, and a district and a commonwealth. Approximately 98% of the population resides in a state. Each region may be further subdivided into a plethora of smaller political entities (cities, towns, counties, townships, etc.). However, political sovereignty rests at the state (or equivalent) level, and smaller entities are not sovereign.

In some historical contexts, "the Americas" refer to what is know known as the Western Hemisphere, or the entirety of the North and South American continents, plus all the islands of the Caribbean. Currently, approximately 50 distinct nation-states occupy those areas.