"After carefully considering conditions on the ground, I have determined that it is necessary to extend the Temporary Protected Status designation for Syria," Homeland Security Secretary Kirstjen Nielsen said in a statement.
"It is clear that the conditions upon which Syria's designation was based continue to exist, therefore an extension is warranted under the statute," Nielsen said.
The extension lasts through September 30, 2019, and Nielsen will review conditions ahead of that date to determine whether it should be extended again or ended.
The US government has stripped similar protection from some 200,000 Salvadorans, 59,000 Haitians and 5,300 Nicaraguans -- some of whom had been in the country for decades.
The Syrian civil war broke out after President Bashar al-Assad's forces carried out a brutal crackdown on protesters in 2011, drawing in countries from around the region as well as the US, Russia and others.
The brutal conflict has killed more than 340,000 people and devastated swathes of the country, pushing millions of people to flee.