The term “Sunbelt” connotes a region defined by its environment. “Belt” suggests the broad swath of states from the Atlantic coast, stretching across Texas and Oklahoma, the Southwest, to southern California. “Sun” suggests its temperate—even hot—climate. Yet in contrast to the industrial northeastern and midwestern Rust Belt, or perhaps, “Frost” Belt, the term’s emergence at the end of the 1960s evoked an optimistic, opportunistic brand. Free from snowy winters, with spaces cooled by air conditioners, and Florida’s sandy beaches or California’s surfing beckoning, it is true that more Americans moved to the Sunbelt states in the 1950s and 1960s than to the deindustrializing centers of the North and East. But the term “Sunbelt” also captures an emerging political culture that defies regional boundaries. The term originates more from the diagnosis of this political climate, rather than an environmental one, associated with the new patterns of migration in the mid-20th century. The term defined a new regional identity: politically, economically, in policy, demographically, and socially, as well as environmentally. The Sunbelt received federal money in an unprecedented manner, particularly because of rising Cold War defense spending in research and military bases, and its urban centers grew in patterns unlike those in the old Northeast and Midwest, thanks to the policy innovations wrought by local boosters, business leaders, and politicians, which defined politics associated with the region after the 1970s. Yet from its origin, scholars debate whether the Sunbelt’s emergence reflects a new regional identity, or something else.