This article presents a large body of qualitative material on healthcare access and barriers for unauthorized immigrants living in the US-Mexico borderlands. The focus is on active sequences of health-seeking behavior and barriers encountered in them. Barriers include direct legal mandates, fear of authorities, obstacles to movement by immigration law enforcement, interaction of unauthorized legal status with workplace and household relations, and hierarchical social interactions in healthcare and wider social settings. At the same time, important resilience factors include community-oriented healthcare services and the learning/confidence-building process that enable the unauthorized to connect to such services. An important finding is that barriers are not discrete factors but rather occur as webs that make solution of challenges more difficult than individual barriers alone. Outcomes include incomplete sequences of care, especially breakdowns in complex diagnoses, long-term treatment, and monitoring of chronic conditions.