As I was reading the 2007 World Almanac (not great literature, but wildly entertaining) I discovered an interesting tidbit about federal land.
The Federal Government owns 3.7 million acres (approx. 11.82%) of North Carolina.
The state of North Carolina owns 765,501 acres (approx. 2%) of the state.
All of this excludes conservations trusts and land owned by city and county government.
For some additional perspective, 87.5% of the state is undeveloped, that final tidbit from Roy Cordato.