This chapter evaluates regionalism across North America, examining its history and contemporary debates. North American regionalism is characterized by its variegated nature: the number of real and imagined regional governance spaces across the continent is due to the different stakeholders that develop new governance spaces to meet specific needs. The chapter describes regionalism in and across all three countries but focuses on the United States. After describing how regionalist discourse evolved over the twentieth century, the chapter explains how regionalism is proposed to solve economic development, bureaucratic, and equity concerns. Canadian regionalism is contrasted to the US case, while supranational regionalism including free trade treaties and international urban regions are forming new regional spaces. The chapter concludes by describing the emerging future of North American regionalism. This includes the speculative planning for megaregional spaces, and a call to engage with the everyday regionalisms that individuals and communities experience.