Borderlands and frontiers impact identity, culture, and social organization. As such, most studies of 18th and 19th century California emphasize the role of the Franciscan missionaries, soldiers, and other settlers in their colonization of the Spanish frontier and the subsequent transformative impacts and reactions of Native Californians (Lucido 2014: 82). By contrast, scholarship that thoroughly examines gender and sexual politics of Alta California is inadequately represented. Even so, the dominant narrative of these studies focuses on how the frontier was utilized to heighten sexualized and engendered hierarchies among male colonists and indigenous women (Lucido 2014: 84; Voss 2008: 304). A microscale analysis of successive generations of women from one of Spanish California’s earliest settler families, the Arballo (m. Lopez) lineage, provides a nuanced examination of colonial women in the frontier. More specifically, this paper interrogates how these women acted both as equally important partners in the colonization of Alta California but also as individual agents. The Spanish-Mexican women central to this paper include: María Feliciana Arballo, María Ignacia de la Candelaria López, María Antonia Natalia Elija “Josefa” Carrillo, and María Ramona la Luz Carrillo.