The presence of Coyotes in NC is generally attributed to yotes escaping the pens and starting a wild population. In eastern NC there is an endangered species called the Red Wolf, Wild coyotes are destined to eliminate the species. Red Wolves are able to breed with coyotes, and the offspring are, obviously, not pure Red Wolf any longer.
In time, there will be no more Red Wolves, just hybreds.
Uncle Alvah is correct. Way back in the early 1980's fox hunters in N.C. began importing (illegally) coyotes from the midwestern states in order to help stock their fox hunting pens. The pens were used to train and run fox hounds without worry of the hounds getting lost or crossing onto someone else's land who didn't want dogs run on it.
My grandfather had one of the largest pens in the state at just under 800 acres. I helped build it, installing over 4 miles of welded-wire fencing through swamps and thickets that had to be cleared with a small dozer. I helped stock it with foxes.
Ironically, in the 1970's fox hunters in NC banded together to get laws passed outlawing trapping foxes in the state. Then, when they began building pens in the 80's they didn't have a (legal) reliable method of keeping the pens stocked with foxes, so they began importing coyotes to help fill them. Only "outlaw" backwoods trappers would trap and keep live foxes, but the supply of coyotes from the midwest was quickly in full swing. The coyotes were hardier and less likely to get caught and killed by the hounds.
Trouble was, those coyotes easily escaped the pens and began establishing themselves across the state. Now they are a nuisance.