While a number of Mende grammars have been written (Aginsky 1935; Innes 1967; Spears 1967; Brown 1982), there is no systematic treatment of its adpositional system. In this paper I introduce Mende’s adpositional system, providing a brief, intuitive definition, according to Talmy’s (1983) schematization. I next consider how to categorize its adpositions as lexical, functional, or polyfunctional. I use five diagnostic tests to show how locatives are similar to putative nominals (and different from functional adpositions), then use two tests to show how they differ from nouns. Based on these tests, I propose a (synchronic) syntactic cline, ranging from nouns to light nouns to locatives and functional adpositions. Finally, I explore whether this analysis can also account for complex postpositions, arguing that the first adposition is always farther to the left on the cline.