A recent population growth forecast by Statistics Estonia said only the nation's two largest cities and Harju County will experience an increase in population in the next 30 years.
Järva and Hiiumaa counties will see the largest drop of around 30 percent by 2040, ETV reported on Thursday.
Other counties are forecast to lose 22 percent of their population on average, and the average age in those counties is also expected to increase.
Population figures in Tartu and Harju counties are forecast to increase by a few percent.
The Statistics Estonia report forecast a total drop of 125,000 in population by 2040.