Saturday, April 14, 2012

The Mason Dixon Line

Between 1763 and 1768, British astronomers Charles Mason and Jeremiah Dixon surveyed what is now the northern border of Maryland and the southern border of Pennsylvania, the State Line.  Each mile they would place a stone marker, one side having a P for Pennsylvania, and  the other side with a M for Maryland.  Every five miles along the line they placed  a "crown-stone."   The crown stone displayed the coat of arms of Lord Baltimore on the south side, and The Penns on the north side (see stone below, second from bottom).  The stones were imported from England and are still in place today!    

The Mason Dixon Line later became the line separating slave states (Maryland) and free states (Pennsylvania), or the line between North and South during the Civil War.  Runaway slaves would try to make it north of the Mason Dixon Line to freedom.  Then they would continue their journey, via safe houses in southern Pennsylvania (part of the Underground Railroad), farther north. 

Not one of the original markers, the obelisk marks the line between Maryland and Pennsylvania.  The same marker is in the above and below pictures.  In the below picture, look out into the grass at the right of the frame and you can see one of the original stones in the field.  It is on private property and I did not want to risk upsetting the owner and wander onto the property without consent.   

Near an I-81 exit at the state line, I found one of the original mile markers.  The P indicates I am on the Pennsylvania side.  

A modern marker near the mile stone (above).

Near the mailbox at the right in the picture is one of the crown stones, placed every 5 miles along the Mason Dixon Line.  This stone happens to be the 100th mile along the Mason Dixon Line. To the left is Maryland.

The coat of arms of Lord Baltimore is still visible on the Maryland side of the crown stone,  The house is in Pennsylvania. 


  1. I saw your post that you were going to photograph this yesterday. That prompted Anais to look up the Mason Dixon line and read about it. You freekin made us learn stuff yesteday! Thanks a lot!!!!!! (By the way, I think it's pretty cool that those old markers are just right there for anyone to see!)

    1. I found a site with GPS coordinates for each stone, and copy and pasted into Google Maps and voila! It showed the exact place each milestone and crown stone were at. I then created a map of my own and was able to use my iPhone while out looking for them. I only mapped three of them, but it's possible to find all of them. The entire Northern and Eastern Maryland borders are Mason Dixon Line.

  2. Another awesomely informative post Pat...

    1. Thank you, Deej! Sometimes the coolest things are close to home. A little research and effort make for a great adventure.