It’s not every day that you stumble upon a historical monument while doing a boundary survey. Although, that’s exactly what happened back in 2009 when I was just a young survey technician. As I was cutting through thick briars ahead of the field crew, I noticed a large stone protruding through the earth. It was a 12″ square monument, sticking out of the ground with the letter “P” engraved on one side and an “M” on the other. I had no idea what I had stumbled upon, until my party chief exclaimed, “that’s a Mason-Dixson stone”. It was remarkable discovery at the time, but it wasn’t until later that I really understood the importance and history of what I had discovered.

The history of this line begins with a border dispute between the British Colonies of Pennsylvania and Maryland during the mid-1730’s. At the time, both claimed the land between the 39th and 40th parallels according to charters granted to each colony. Although, the location of this line was never agreed upon, and each proprietor claimed more land than the other was willing to give up. Violence erupted between settlers claiming various loyalties to Maryland and Pennsylvania over property rights and law enforcement.

In 1760, the British crown demanded the issue be resolved and a resolution was reached to hire the English team of Charles Mason and Jeremiah Dixon to survey and establish the northern border between Pennsylvania and Maryland. Charles Mason (an astronomer) and Jeremiah Dixon, (a well-known surveyor) worked together between 1763 and 1767 to set this border. The line was marked by stones every mile and “crown stones” every 5 miles. It was laid out at 39 degrees 43 minutes north latitude and stretched 233 miles, 15 miles south of Philadelphia. The stones were quarried and carved in England and then shipped to the new world. One hundred thirty-three stones were originally set by Mason & Dixson, but below is a map showing milestone markers No. 3, 4 & 5 that we located during the survey I was working on.

This line would also go on to figure prominently in the Missouri Compromise of 1820 and theoretically divide the north from the south in the civil war. It later became informally known as the border between the free states the then slave states. For many, it symbolized the line of freedom.

That day in the woods, while standing in front of one of the most famous survey monuments in American history, I was grateful to be a part of this profession that allows me to tangibly walk in the steps of our forefathers.