This paper demonstrates how the tools of dialect geography may fruitfully lend a new perspective to historical data in order to address the lingering questions left by previous analyses. A geographic examination of Survey of English Dialects data provides evidence in favor of a push-chain analysis of the Great Vowel Shift, in which the Middle English high-mid long vowels raised before the high long vowels were diphthongized. It is also demonstrated that the so-called “irregular” dialect outcomes, which have previously been cited as evidence for a lack of unity of the Great Vowel Shift, are no longer problematic when viewed in the light of a theory of dialect contact, and can in fact refine our understanding of the chronology and geographic extent of the shift itself.