While transnationalism has emerged as a growing area of interest in Writing Studies, the field has not fully examined how migrants' movement across national borders shapes their literacy practices. This article offers one answer to this question by reporting on an ethnographic study of the transnational religious literacies of a community of undocumented Brazilian immigrants in a former mill town in Massachusetts. A grounded theory analysis of (a) participants' accounts of their literacy experiences before and after migration, (b) their writing, and (c) ethnographic observations reveals the following: As participants crossed a border and were excluded from state documentary projects, they began to write within other literacy institutions, namely, transnational churches, that have historically documented subjects and whose reach extends across national borders. The author concludes that as the field of Writing Studies continues to explore transnational literacies, it would do well to take into account the materiality of national borders, which can shape possibilities for written communication in a global context. (Contains 1 table and 3 notes.)