The Los Angeles Times said Wednesday the injunction was seen by environmentalists as a victory against the Bush administration's efforts to relax land-use restrictions in the West.
U.S. District Judge Susan Illston said the government's management plans for the area violated the Endangered Species Act.
The injunction applies to nearly a half-million acres of desert along the California-Arizona state line that is home to the desert tortoise, a creature that is protected by the act.
The area is also a favorite of off-road enthusiasts, whom the Times said have blamed drought and marauding ravens for the tortoise's decline.
Off-roader groups were miffed at the ruling, although the Bureau of Land Management said 1.7 million acres in the area remain open to vehicles.