N.C. Gen. Stat. § 75-4: Contracts to be in writing.

No contract or agreement hereafter made, limiting the rights of any person to do business anywhere in the State of North Carolina shall be enforceable unless such agreement is in writing duly signed by the party who agrees not to enter into any such business within such territory: Provided, nothing herein shall be construed to legalize any contract or agreement not to enter into business in the State of North Carolina, or at any point in the State of North Carolina, which contract is now illegal, or which contract is made illegal by any other section of this Chapter. (1913, c. 41, s. 4; C.S., s. 2562.)