This document summarizes research on how the Affordable Care Act (ACA) affected unauthorized immigrants' access to healthcare in the United States. It discusses how the ACA formally excluded unauthorized immigrants, 'brightening' the boundary between them and those eligible for coverage. While some localities pursued more inclusive policies, formal barriers to specialty care remained. Informal barriers like documentation requirements also deterred some unauthorized immigrants from seeking preventive care. The research examined these issues through interviews in San Francisco and Boston with immigrants, healthcare providers, and leaders."