Blidaru is an ancient Dacian fortress near Costeşti village in Hunedoara County, Romania.This is one of six forts built in murus dacicus style in the Orastie Mountains.The other five forts include Sarmizegetusa, Piatra Roşie, Costeşti, Căpâlna and Băniţa.

The fortress, situated on the Blidaru hill, at an altitude of 703m, includes two unified rooms and with six strong observation towers. They were created in the 1st centuries BC and AD as protection against Roman conquest.