Kurdish is often portrayed as a linguistic unity, but an examination of phonological structures in the language reveals substantial internal variation. In this study, we examine the geographic distribution of vowels and consonants in the phonological inventories of 125 Northern Kurdish (Kurmanji) and Central Kurdish (Sorani) varieties in the Database of Kurdish Dialects, and their patterning in individual words from all of these data sets. The data reveal a stable set of core vowels and consonants, along with peripheral phonemes of both types that demonstrate a high level of variation in geographic distribution and frequency. Segments with significant distributional restrictions include front rounded vowels, uvular consonants, a contrastive aspirated stop series, emphatic alveolar obstruents, and pharyngeals ʕ and ħ. An analysis of these patterns gives modest confirmation of the well-known Northern vs. Central Kurdish dialect division, but shows that the phonological distinction between the two is best characterized in terms of tendencies rather than exact, regular correspondences. Beyond many other individual isoglosses in the data that cross-cut one another, there is a weak pattern of transition between the two major dialect areas; limited diffusion of phonological innovations to varieties at the geographic periphery of the language; and more direct influence of language contact on the phonological structures in certain regions. Alongside these various configurations of areal distribution, and in contrast to them, there is a strong, overarching pattern of non-directional phonological variability among varieties, which points to the local nature of phonological changes across the language area.