“Personal parishes,” defined in the Catholic Code of Canon Law not by territory but by service to a particular population or special need, represent an emergent but understudied model of parish development in the U.S. Catholic Church. With little discussion across dioceses or attention from scholars of religion, their presence in the United States has grown rapidly in the past two decades as a consequence of changes in canon law, increased papal receptivity, and advocacy among Catholics both lay and ordained. Personal parishes accommodating various ethnic groups, worship styles, and purposes emerge at the intersection of lay mobilization and elite validation, as local bishops decide when and which Catholic communities may receive the canonical status of “parish.” My proposed survey of all U.S. dioceses and three follow-up case studies will shed light on how local religion is being cautiously re-conceptualized to accommodate diversity among adherents and the declining relevance of geographic boundaries in religious organization. Findings, accessible via written publications and an online database of all personal parishes, will catalyze conversations among pastoral leaders seeking to foster unity in diversity and introduce non-territorial communities of faith.