All over the United States, adult ESL programs enroll students who are undocumented immigrants, often unbeknownst to the instructors who teach them. During the COVID-19 crisis, adult ESL enrollments decreased overall, but most especially for the undocumented immigrants who were most disadvantaged during the crisis. In order for program administrators and instructors to better understand the situation, this article explores who those with undocumented status are, why they have come to the US, and how well they are being served by public and private institutions and organizations. It details the nationality and settlement patterns of the undocumented immigrants as well as reasons for their departure from their homes around the world and their journeys to the United States. This article also discusses solutions for issues undocumented students face, including pedagogical approaches addressing the needs of undocumented learners given their migration experiences, funding to expand classrooms and hire teachers qualified to meet the needs of these students, and better collaboration between public schools and nonprofit organizations.