Although both the urban and rural landscapes of Roman Italy have received due attention in current debates on the Roman economy, this is less true for the highly variable group of intermediate sites, here conveniently labelled as ‘minor centres’, and their role within economic networks. This contribution focuses attention on two such sites, Forum Appii and Ad Medias, situated in the Pontine plain (Lazio, central Italy) along the Via Appia. After addressing issues of definition and the current state of research, we shall approach the potential functions of such sites through geographic models. Next, we discuss the results of a programme of geophysical surveys and field walking on both case-study sites. The results obtained suggest that, although far from being a uniform settlement class, minor centres could perform crucial functions within local and regional economies. Based on the present data, Forum Appii developed into a centre of craft production and, with its river port, also became a trade hub of regional importance. Ad Medias functioned primarily as a small centre provisioning and servicing travellers and the local rural population. To conclude the article, we consider the implications of the results obtained in terms of future research strategies.