Mason-Dixon Line accuracy hailed as 'extraordinary'
Mason-Dixon Line expert David Thaler says the map produced at the end of the five-year survey is one of America's most important documents.
He described it as being equivalent to the Declaration of Independence.
You can see more on this story on Inside Out on BBC One in the North East and Cumbria on Monday at 19:30 BST
30 Aug 2017
- From the section England