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The Mason and Dixon Line Preservation Partnership was established in November, 1990 to inventory the stones that mark the Mason and Dixon line and determine ways to preserve the stones from further loss and deterioration.  Ultimately, we hope to replace the stones, which have been destroyed or damaged beyond repair. 

The Partnership has also undertaken the major task of locating the stones using the Global Positioning System (GPS).  This method of surveying uses a constellation of satellites, which orbit the Earth.  Through this procedure, we will be able to obtain the Latitude and longitude of the stones to sub-centimeter precision.

Though often associated with the issue of slavery and the division of  “north” and “south”, the history of the Mason and Dixon Line predates the Civil War by over 200 years.  The “Mason and Dixon” is named after Charles Mason and Jeremiah Dixon, English astronomers; surveyors and mathematicians hired by the Penn and Calvert families to establish the long disputed boundary. 

The Inventory

The initial objective of the Mason and Dixon Line Preservation Partnership (MDLPP) was to conduct an inventory of the monuments that mark the line. Mrs. Alice Martin had conducted the last comprehensive inventory of the line in the early 1980's on behalf of the State of Maryland. The inventory conducted by Mrs. Martin resulted in a very detailed report on the condition of the line and was very helpful in the preparation of the MDLPP inventory.

During 1991, the members of the MDLPP conducted an inventory of the first 132 miles of the Mason and Dixon line. The results of the inventory showed that 10 of these monuments were destroyed, missing or damaged beyond repair. Since 1991, we have continued with the inventory and many of the stones inventoried in 1991 were revisited as a part of the location of the stones using the Global Positioning System (GPS). The monuments that remain to be inventoried are located in the remote and mountainous sections of West Virginia and western Maryland. These monuments are, for the most part well protected, and will be inventoried as the project progresses.

The State of Maryland is required by law to conduct an inventory of the state boundaries once every ten years. A copy of the inventory and photographs were submitted to the State of Maryland upon completion.  These reports were used to satisfy the 10 year requirement for 1990 and 2000, thus saving the taxpayers of Maryland thousands of dollars which otherwise would have been spent to conduct an inventory.

The inventory was conducted by the MDLPP to document the location and condition of the stones. Sketches of the site were made to assist in the future location of the stones. The stones were also photographed to allow for a comparison after future visits. The Latitude and Longitude positions of the stones will be useful to future generations to reestablish the position of stones that are damaged or destroyed.  The positions established by MDLPP have already proven valuable in locating the position of Mason and Dixon milestone 9 that had been reported missing for many years.  The position of the stone was calculated using the locations of other stones to the east and west of the calculated position.  An excavation was made in the plowed farm field and the stone was recovered. These positions were also used to conduct an analysis of the work and procedures implemented by Mason and Dixon during the survey.

Promoting History

An important objective of the MDLPP is to promote a true and factual history of the Mason and Dixon Line. The Mason and Dixon Line has come to be known as the line which divided the free states from the slave states or north from south. The true history of the line has been muddled through years of folklore and hearsay. There are many who have been led to believe that the stones that mark the line are accurate to within 1/2 inch of the intended location. Others believe that to be from "way down south in Dixie" stems from the fact that they live south of the Mason and "Dixon" Line. (Conversely, I suppose it could be said that a Vermonter is from "way up north in Masey"). Our objective is to dispel such folklore and promote a factual history of the line.

GPS Survey

The stones that mark the Mason and Dixon Line have remained stoically in their position for over 230 years. Through the Revolutionary War, Civil War, Industrial Revolution and 2Oth Century expansion and growth, the stones set by Messrs's Mason and Dixon have acted as sentinels, patiently marking the line which had for so long been a matter of dispute. Time, however, is beginning to take its toll.

In the 230 years since the completion of the survey, there have been numerous inventories conducted as well as surveys to re-monument sections of the line. The most comprehensive "Re-survey" was conducted from 1901 - 1903 on the Pennsylvania and Maryland section of the line. During this re-survey, the stones were re-set in a base of concrete. The stones which were missing were replaced with replica stones as near as could be determined to the original position based upon the information contained in the journal of Mason and Dixon.

During the 1960's and 1970's, NOAA using conventional geodetic surveying methods surveyed the north-south line between Maryland and Delaware. The position of the stones on the north-south line, therefore are known and can be re-established in the event a stone is destroyed or lost. This cannot be said of the stones along the east-west line between Maryland, West Virginia and Pennsylvania. If a stone is lost on this section of the line, it would require locating several stones to the east and west and, using the information contained in the original journal, the original position of the stone could be approximated. By conducting a GPS survey on the stones, we are determining the position of the stones to sub-centimeter positional accuracy. This will allow the position of the stone to be accurately re-established in the event the stone is damaged or destroyed.

The GPS survey of the Mason and Dixon line began in April 1995. Since that time, we have conducted numerous GPS session with the assistance of many volunteers. Some sessions involved 17 volunteers manning 15 dual-frequency receivers. To date, we have established the position of 120 stones. The control networks for the sessions have been tied to existing HARN and 1st order geodetic control.

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