The federal government has listed Peavey Plaza in Minneapolis on the National Register of Historic Places.
The move comes as the city and historic preservationists battle in court over the future of the site.
The Minneapolis City Council voted last year to demolish Peavey Plaza, arguing it was obsolete, inaccessible and conducive to crime. The Washington D.C.-based Cultural Landscape Foundation is suing to block the demolition.
The group's President Charles Birnbaum said having Peavey Plaza listed strengthens the case to save it.
"The city has questioned, time and time again, the integrity and significance of this landscape," Birnbaum said. "And now we have the highest authority, the keeper of the register, working with the state, approving the designation on Jan. 14.
A spokesman for Minneapolis issued a written statement saying the listing "does not impact the path the city is on." Peavey Plaza was completed in 1975. A Hennepin County judge will hear arguments on its future in February.