What's the purpose of the Mason-Dixon Line?

The Mason–Dixon line, also called the Mason and Dixon line or Mason's and Dixon's line, is a line separating four U.S. states, forming part of the borders of Pennsylvania, Maryland, Delaware, and West Virginia. The line was established to end a boundary dispute between the British colonies of Maryland and Pennsylvania/Delaware.

But historically, it came to be seen as demarcating the North from the South in the U.S. and is still used today in the figurative sense of a line that separates the Northeast and South culturally, politically, and socially.