This experimental session brings together scholars who seek to historicize key features of urban informality. All scholars with research and publications on this topic, each will give brief 7-min presentations all focused on the idea of urban informality, including informal housing, settlements, and aspects of the informal labor and selling economies. The short presentations will be followed by facilitated discussion with the audience. As a term and concept, informality emerged in the mid to late twentieth century as a way to explain the particular dynamics of that era in growing cities. Despite its significance in the social sciences and public policy, urban informality has gone relatively unexplored by historians of Latin America. Anchored in local contexts and communities of cities in Mexico, Chile, and Brazil, the panel will underscore the central role informality played in the historical development of Latin America’s cities. Panelists will discuss how they approach this concept as historians and the challenges they encounter in their own historical research on urban informality. Specifically, the history of urban informality will be explored through the networks, politics, and regulation of urban sellers and street workers; through aspects of property rights and regimes of squatter settlements, including their access to and experiences around urban public services; and to the question of how race functioned as a defining aspect of informality in certain historical contexts. Though drawn from individual projects, the purpose of the panel is to highlight broader conceptual or methodological questions historians confront when carrying out research on urban informality. What kinds of archival material can be utilized to research activities or places not formally regulated by the state? How can historians study the long-term effects of formalizing an informal space or practice over time? What are the relevant historical antecedents and historical connections to the concept of informality and the informal economy from the mid to late nineteenth and early twentieth centuries in Latin America? How do we not only document that informality has a history, but also begin to understand how informality is a part of history, integral to larger questions about things like state formation, the role of law, welfare, inequality, and the environment? The presenters and participating audience will grapple with these questions.