Eretum (Greek: Ἠρητόν), was an ancient town of the Sabines, situated on the Via Salaria, at its junction with the Via Nomentana, a short distance from the Tiber, and about 30 kilometres (19 mi) from Rome.
From the mention of its name by Virgil among the Sabine cities which joined in the war against Aeneas, we may presume that it was considered as an ancient town, and one of some importance in early times; but it never bears any prominent part in history, though from its position near the frontiers of the Sabine and Roman territories, and on the line by which the former people must advance upon Rome, it was the scene of repeated conflicts between the two nations. The first of these occurred in the reign of Tullus Hostilius, during the war of that monarch with the Sabines; his successor Tarquinius Priscus also defeated the Etruscans, who had taken advantage of the friendly disposition of the Sabines to advance through their territory, at Eretum; and Tarquinius Superbus gained a decisive victory over the Sabines in the same neighbourhood. Under the Roman republic also we find two victories recorded over the Sabines at the same place, the one by the consuls Postumius and Menenius in 503 BCE, the other by Gaius Nautius Rutilus in 458 BCE. During the decemvirate also the Sabines established their headquarters at Eretum, whence they ravaged the Roman territory. It is again mentioned in the Second Punic War as the place whence Hannibal diverged to attack the shrine of Feronia in Etruria, during his advance on Rome (or, according to others, on his retreat) by the Salarian Way. But though its position thus brings it frequently into notice, it is clear that it was, under the Roman dominion at least, a very inconsiderable place. Strabo says it was little more than a village, and Valerius Maximus terms it vicus Sabinae regionis. Pliny does not even mention it among the towns of the Sabines, nor is its name found in the Liber Coloniarum: hence it is almost certain that it did not enjoy municipal privileges, and was dependent on one of the neighbouring towns, probably Nomentum (modern Mentana). But its name is still found in the Itineraries as a station on the Salarian Way, and it must therefore have continued to exist as late as the fourth century. From this time all trace of it disappears.