This article explores the formal and functional organization of Romance demonstrative systems, providing a detailed empirical overview of the vast microvariation attested in standard and non-standard Romance varieties. Despite highlighting a considerable number of distinct demonstrative systems based on different superficial person contrasts, it is argued that the underlying number of systems can effectively be reduced to a much smaller number of systems based on a finite number of options. In particular, it is argued that the feature geometric analysis of person developed by Harley & Ritter (2002) makes some specific predictions about the range and types of person combinations, and hence by implication also the types and natural classes of demonstrative systems, that are cross-linguistically available. Adopting these assumptions, it is argued that these differing person feature specifications can be profitably modelled in terms of a set of hierarchically-organized interrelated parametric options in accordance with much recent work developed within the ReCoS group.