“…Finally, to the best of our knowledge, we provide the first piece of systematic evidence in support of the long-standing idea that historical migration patterns in the US were influenced by climate similarity (Coolidge, 1926;Steckel, 1982;Fischer, 1989). 7 By shedding light on a new, important driver of migration-namely, climate similarity-at a critical point in American history, we also contribute to the large literature on US internal (Bazzi et al, 2020(Bazzi et al, , 2023aZimran, 2023) and international (Eriksson, 2020;Abramitzky and Boustan, 2022;Collins and Zimran, 2023) migration between 1850and 1940 As early as the 1600s, climate matching was an important consideration for English migrants to North America and the West Indies, who expressed "profound anxiety" about the health and productivity impacts of climates that diverged from England's temperate climate. Sir Ferdinando Gorges, who founded the Province of Maine in 1622, argued that New England was "more suitable to the nature of our people, who neither finde content in the colder Climates, nor health in the hotter; but (as hearbs and plants) a ect their native temperature, and prosper kindly no where else" (Kupperman, 1984).…”