The Goff surname was adopted in Rockingham Co., NC.
The founder of this Goff family is William Goff b. 1781 Rockingham Co., NC.
A male Goff descendant of William Goff b. 1781 took the YDNA-67 test. Matches with men with the surnames Gilliland, Gilleland, Gillilan, Gilland and Gillon were prominent. An 1811 Rockingham Co., NC agreement sheds light on these YDNA matches. In that agreement, Robert Gilliland of Rockingham Co., NC gave land to Nancy Goff in recognition that he was very old and not able to care for himself. He noted that Nancy had lived with him for 35 years (i.e., since ca. 1776) and that her son William Goff was born and raised in his house.
While there is more research to be performed, the simplest explanation for the genetic and paper trail evidence is that Robert Gilliland was the father of William Goff b. 1781 Rockingham Co., NC.
There is little doubt about the origin of this Goff family so no further DNA testing is suggested.