To examine the intersection of religion and ethnicity among Mexican immigrants, this volume takes readers into the vibrant neighborhoods of central Santa Ana, California, a Mexican-majority metropolis with high rates of religious participation. Ethnic Mexicans have traditionally been characterized by their religiosity, and have historically been marked as ethno-racially distinct from the white majority. On the one hand, this volume investigates whether Mexican ethnicity is indeed a cohesive organizing principle that continues to mark Mexicans as distinct. On the other hand, the volume examines the mechanisms of religion that sustain or alter in-group understandings of ethnicity. To highlight the mechanisms that shape ethnic identity, the volume takes a comparative approach, juxtaposing the experiences of Catholic and evangelical Mexican immigrants, the two largest religious groupings in the city. Through five years of participant observation within formal and informal Catholic and evangelical spaces in Santa Ana, and based on in-depth interviews of fifty parishioners, this book argues that religious affiliations set Catholics and evangelicals along diverging trajectories of ethnic identity construction. In particular, the author argues that while Mexican Catholics ritualize a sense of their ethnic past, Mexican evangelicals posit a rupture with the past rooted in conversion. Catholics and evangelicals’ diverging understandings of ethnic community and of ethnic identity manifest as distinct practices of ethnic space.