Ehrmantraut County is one of the five counties of Carraway Island (the other four being Barrymore, Lewis, Glass, and Walsh, plus the independent city of Jan Beach). The county is located in the northeastern corner of the island.

With a population of 1,255,801 as of the 2014 census, it is the most populous county on Carraway Island.

The county seat is Adustelan, which also serves as the nation's capital.