Originally privately owned. The state of Georgia bought the Stone Mountain carving in like the 60s or 70s, and owns it now.
No one in the State Legislature is going to vote to remove Stone Mountain. Even black Democrat Hank Johnson, who represents the district in which Stone Mountain resides, said in 2015 after the whole Roof-inspired anti-Confederacy media hysteria thing to leave Stone Mountain alone.
1958. The Venables transferred it to the Memorial Association in 1956, and the Association transferred it to the state in 1958.
These people are trying to destroy our country's history. Someone in authority (if there is such a critter anymore) needs to put their foot down and say no more.