Reactions of the uranyl cation (UO₂²⁺) with 4-halopyridinium ions (X = Cl, Br, I) in high halide media (X′ = Cl, Br) have produced six novel compounds, the structures of which have been determined by single crystal X-ray diffraction (XRD). The compounds can be divided into two categories based on the different modes of hydrogen bonding and halogen–halogen interactions present in the crystal structures, with one group showing approximately Type I halogen–halogen interactions and the second showing Type II. Presented is a discussion of the relative strengths of the interactions as a function of halogen size.