The Kentucky-born singer was part of the Grammy award-winning duo The Judds, performing with her daughter Wynonna.
The pair had a string of hits, including Love Can Build a Bridge, and were due to be inducted to the Country Music Hall of Fame on Sunday.
But Judd's death was announced a day earlier by Wynonna and her other daughter Ashley, an actor.
In a statement, the sisters said they had lost their "beautiful mother to the disease of mental illness" and were "navigating profound grief."
No further details have been released about the cause of her death.
