The Trump administration has decided to cancel permits that allow nearly 200,000 people from El Salvador to live and work in the US.
They were granted Temporary Protected Status (TPS) after earthquakes rocked the Central American country in 2001.
Salvadoreans now have until 2019 to leave or face deportation, unless they find a legal way to stay.
The Trump administration has already removed TPS protection from tens of thousands of Haitians and Nicaraguans.
Protections for Salvadoreans were set to expire on Monday, after nearly two decades of holding the humanitarian status due to the impact of the natural disaster that killed more than 1,000 people.
The latest announcement comes four months after the government said it planned to scrap an Obama-era scheme, Daca, that protected young undocumented immigrants, mostly Latin Americans, from deportation.
Lawmakers in Congress have been given until March to decide on the fate of the 800,000 so-called Dreamers affected by the Daca decision.