The Biden administration and more than 4,000 migrants who were separated from their families at the U.S.-Mexico border by the Trump administration reached a legal settlement that allows the families to live and work in the U.S. for three years while receiving housing, mental health and legal assistance to apply for asylum.

The deal may end one of the darkest chapters in U.S. immigration policy, in which families crossing the U.S.-Mexico border illegally in 2017 and 2018 were systematically separated.