Hiiu County (Estonian: Hiiu maakond) is one of the 15 counties of Estonia. It is the smallest county both in terms of area and population. It is made up of Hiiumaa, the second-largest island of Estonia, and several smaller islands near it.
The county has 1 rural municipality - Hiiumaa Parish. The only urban settlement, Kärdla, is part of the parish since 2017.