In this article, we examine locational constructions (including existentials, locatives, and possessives) in a number of languages. Morpho-syntactically, locationals resemble or are related to one another in word order, in case marking, and in the choice of verbs. In semantics, the relatedness lies in the definiteness effect, in the locative feature, and in the mutually defining relationship between the semantic elements within each construction. As is recognized by Heine (1997), Stassen (2001) and others, the existential is one of the major sources from which possessives are derived. Basically, possessive constructions are existentials whose locative elements are prototypically human. We argue that locational constructions are relational processes and that they can be integrated into a systemic network with respect to two semantic features, i.e., the definiteness of the existent element and the humanness of the locative element. This systemic relationship between locationals has implications for the description and comparison of languages within the Systemic Functional Grammar framework, particularly where locationals are concerned.