CSA General George Washington Custis Lee.
Source: Intimate Strategies of the Civil War, edited by C.K. Bleser and L.J. Gordon, page 46.
bonus Answer: 22. Were born in NC
Except Brig. General James H. Lane, born in Matthews Courthouse, VA.
North Carolina in the American Civil War-Wikipedia
Edit - The term "notable" is very subjective. Any number of widely varying lists of notable people can be prepared, depending on the criteria used to decide who was notable and who was not.
It is apparent that, for the purposes of the list used as the basis for the official answer, "Notable Civil War Leaders from North Carolina" were defined as Confederate generals who were living in North Carolina at the time the war started. However, since this point was not clarified, I have to accept all the answers that players gave, assuming that each player came up with his or her own definition of "notable" and then counted the notable leaders on that basis.
I am somewhat surprised to note that the official answer, based on the 23 notable leaders listed in the indicated source, says that 22 of those 23 were born in North Carolina and James H. Lane was the only one who wasn't born there. Two of the players who cited the same source also stated that James H. Lane was the only one who wasn't born there. According to every source I checked, Daniel Harvey Hill was born in South Carolina, not North Carolina.
Hoosier