For a century, the Ethiopian city Jigjiga was known as a dusty hub of cross-border smuggling and a hotbed of rebellion on Ethiopia's eastern frontier. After 2010, it transformed into a post-conflict boomtown, becoming one of Africa's fastest-growing cities and attracting Somali return-migrants from across the globe. This study examines Jigjiga's astonishing transformation through the eyes of its cross-border traders, urban businesspeople, and officials. Daniel K. Thompson follows traders and return-migrants across borders to where their lives collide in the city. Analysing their strategies of mobility and exchange, this study reveals how Ethiopia's federal politics, Euro-American concerns about terrorism, and local business aspirations have intertwined to reshape links between border-making and city-making in the Horn of Africa. To understand this distinctive brand of urbanism, Thompson follows globalized connections and reveals how urbanites in Africa and beyond participate in the “urban borderwork” of constructing, as well as contesting, today's border management regimes.