The Regional Plan Association has produced four comprehensive regional plans for the New York, New Jersey, and Connecticut metropolitan region since its foundation in 1922. This book examines the evolving role of design in the first three plans and presents the design initiatives of the Fourth Regional Plan (2017) in depth. The new plan seeks to shift the focus of regional planning from a traditional center-to-periphery hierarchy to an expanded notion of "corridor" that includes transportation, ecology, access, and equity. Funded by the Rockefeller Foundation, this collaborative initiative of the Regional Plan Association, Princeton University, and four innovative design teams produced design proposals for four regional corridors: the Highlands (forest corridor), the Bight (coastal corridor), the Inner Ring (suburban corridor), and the Triboro (city corridor).