Iademarco is a surname that dates back to before the 16th century and is uniquely dervived from Mirabello Sannitico, a small village in the region of Molise in Southern Italy.
Based on an unpublished ethnographic study, several surnames are highly distinctive to this town; such that if encountered anywhere in the world, could likely be traced back to Mirabello: Centritto, Fantacone, Iademarco, Iafigliola, Margiasso, Spicciati, Sulmona, and Volpacchio.