I lived in NC for almost 18 years before moving north to be close to elderly parents. I love the state and the OBX is my favorite vacation spot. The term Tar Heel" is an interesting term. During my time living in NC, I remember being told the term had to do with the NC in the CW and the name "Tar Heel" was given to the NC soldiers by General Robert E. Lee. I have no idea if the story is factual, but I like it. A quick search this morning found the same information
here.