Kobarid has been inhabited since prehistoric times. Archaeological remains from the Hallstatt period have been found in the area. The nearby Tonocov Grad archaeological site has remains of 5th-century Roman buildings, when the area was located in the forefront of the Claustra Alpium Iuliarum defense system. The settlement was an important base on the Roman road from Forum Iulii (present-day Cividale del Friuli) up to the Predil Pass and the Noricum province.