The article discusses the emergence of zoning atlases as powerful tools for housing reform advocates, exemplified by Montana’s successful case. It outlines the National Zoning Atlas, a collaborative effort aiming to map zoning regulations across the US at a neighborhood level. Led by Cornell University’s Sara Bronin, the project aims to shed light on restrictive zoning codes, despite the challenges posed by the complexity and frequent changes in these regulations. The article highlights the potential of zoning maps to drive policy change, as seen in Connecticut, where such maps have informed zoning reform efforts. However, it also acknowledges the limitations of mapping alone in addressing the complexities of housing development challenges. The article concludes by discussing ongoing efforts in other states to develop similar zoning atlases and emphasizes the need for comprehensive solutions to tackle housing inequality and affordability.