This paper finds that the US undocumented population from Mexico declined by 1.3 million people from 2010 to 2017, including a decrease of 400,000 from 2016 to 2017. For the first time ever, Mexican nationals constitute less than half of the total US undocumented population. The paper also finds that visa overstays contributed significantly more to the population of newly undocumented residents than illegal border crossers from 2010 to 2017. It recommends that the administration and Congress work together to: 1) provide more resources to the US Department of State for their visa-issuance work and 2) pass legislation to legalize the DREAM-Act eligible population, long-term Temporary Protected Status beneficiaries, and “intending immigrants” with US citizen or lawful permanent resident family members. These findings reveal a disconnect between public discourse on the border wall and empirical data, and argue for more nuanced and evidence-based responses to undocumented migration.