Debbie:
The information I am sharing has come from a book entitled "The Thigpen Tribe." It has been found to have some inaccuracies, so this information must me taken with a grain of salt.
The original family that came from the UK was named PHIPPEN or FITZPEN during the mid 1600's. Somewhere during the move the name was changed to Thigpen. I have not been able to find any documentation to substantiate this, but my time to look is limited. They evidently settled in North Carolina around what is now Edgecombe County. As you well know, they have dispersed throughout the U.S.
I would certainly like to find out about your Great-Grandmother's family to try and tie them in. Let me know if I can assist your further.
Regards....