The Nervii were one of the most powerful Belgic tribes, living in northern Gaul at the time of its conquest by Rome. Their territory corresponds to the central part of modern Belgium, including Brussels, and stretched southwards into French Hainault. During their 1st century BC Roman military campaign, Caesar's contacts among the Remi stated that the Nervii were the most warlike of the Belgae. In times of war, they were known to trek long distances to take part in battles. Being one of the distant northern Belgic tribes, with the Menapii to the west, and the Eburones to their east, they were considered by Caesar to be relatively uncorrupted by civilization.
The territory of the Nervii had its western and northwestern border on the Scheldt (French Escaut) river and stretched in the south through Hainaut to the forests of Arrouaise and Thiérache. To the east, the boundaries are unclear but it is possible that they stretched as far as the Dyle river valley in the north, near Louvain, and the Meuse in the south in modern Wallonia, near Namur. An oppidum found near Asse may have belonged to them but it was isolated and near to the territory of the Menapii. A large population occupied the southern territories, near the river Sambre with the biggest being at Avesnelles, near Avesnes-sur-Helpe. Caesar also mentions smaller tribes who were expected to contribute troops to Nervian forces; Levaci, Pleumoxii, Geidumni, Ceutrones, and Grudii.