Measuring over 10,000 miles, the Great Lakes coastline, known as the “third coast,” is longer than the Atlantic and Pacific coastlines of the United States combined. It is difficult to overstate the history and future of the region as both a contested and opportunistic site for urbanism. Envisaged as a comprehensive “atlas,” this publication comprises in-depth analysis of the landscapes, hydrology, infrastructure, urban form, and ecologies of the region, delivered through a series of analytical cartographies supported by scholarly and design research from internationally renowned scholars, photographers, and practitioners from the disciplines of architecture, landscape, geography, planning, and ecology. This publication was awarded with a grant from the Graham Foundation for Advanced Studies in the Fine Arts.