Numidia (i. e. land of Nomads), ancient country in North Africa, nearly co-extensive with Algiers, the inhabitants of which were of the Berber race, were brave but treacherous, and excelled in horsemanship; sided at first with the Carthaginians in the Punic Wars (q. v.), and finally with Rome, till the country itself was reduced by Cæsar to a Roman province.