The case filed on behalf of Iraqi immigrants on June 15 argued that they would face persecution in Iraq because they are considered ethnic and religious minorities there.
A US federal judge on Monday halted the deportation of more than 1,400 Iraqi nationals from the country.
The development marks the latest legal victory for the Iraqi nationals facing deportation in a closely watched case.
US District Judge from Michigan Mark Goldsmith, granted a preliminary injunction requested by lawyers from the American Civil Liberties Union (ACLU), who argued the immigrants would face persecution in Iraq because they are considered ethnic and religious minorities there.
Goldsmith said the injunction provides detainees time to challenge their removal in federal courts.
He said many of them faced "a feverish search for legal assistance" after their deportation orders were unexpectedly resurrected by the US government after several years.
Goldsmith wrote, in his 34-page opinion and order, that the extra time assures "that those who might be subjected to grave harm and possible death are not cast out of this country before having their day in court."
The decision effectively means no Iraqi nationals can be deported from the US for several months.
It was not immediately known whether Goldsmith's ruling would be appealed by the US government.
A representative for the US Attorney's Office in Detroit did not immediately respond to a request for comment.
There are 1,444 Iraqi nationals who have final deportation orders against them in the US, although only about 199 of them were detained in June as part of a nationwide sweep by immigration authorities.
The ACLU sued on June 15 to halt the deportations of the detainees. They argued the Iraqis could face persecution, torture, or death because many were Chaldean Catholics, Sunni Muslims, or Iraqi Kurds and that the groups were recognised as targets of ill-treatment in Iraq.
Those arrested by immigration authorities had outstanding deportation orders and many had been convicted of serious crimes, ranging from homicide to weapons and drug charges, the US government said.
Goldsmith sided with the ACLU, expanding on June 26 an earlier stay which only protected 114 detainees from the Detroit area to the broader class of more than 1,400 Iraqi nationals nationwide.
Goldsmith's Monday decision came hours before that injunction was set to expire.