On this Day in History: Eight-year-long Cresap’s War between Maryland and Pennsylvania ends

On this Day in History
On May 25, 1738, a treaty ended The Conojocular War, also known as Cresap’s War, between Maryland and Pennsylvania. The conflict began eight years earlier, in 1730, due to boundary disputes and eventually escalated into military involvement by 1736 and 1737.

Early settlers faced challenges traveling westward due to the wide and rocky Susquehanna River. To aid their safe crossing, entrepreneurs established ferry operations. One of the notable ferry operators was Thomas Cresap, a rugged frontiersman from Maryland. In 1730, Cresap established the “Blew Rock” (now Blue Rock) ferry operation at his “Pleasant Garden” plantation, half a mile south of the current location of Blue Rock. Unfortunately, his activities during this time contributed to a bitter border dispute between Maryland and Pennsylvania, which sometimes turned violent.

The dispute had originated decades earlier from somewhat confusing proprietary grants by King Charles I to Lord Baltimore (Maryland) and King Charles II William Penn (Pennsylvania).

Pennsylvania’s Charter (1681) specified that the colony was bounded “on the South by a Circle drawne at twelve miles [19 km] distance from New Castle Northward and Westward unto the beginning of the fortieth degree of Northern Latitude, and then by a streight Line Westward….” Later surveys established that the town of New Castle lay a full 25 miles south of the fortieth parallel.

Maryland insisted that the boundary be drawn at the fortieth parallel specified in the Charter. At the same time, Pennsylvania proposed that it be drawn by an elaborate method that purported to compensate for the geographic misunderstanding on which the Charter had been based. This proposal placed the boundary near 39 36′, creating a 28-mile strip of disputed territory.

Because the fortieth parallel lay north of Philadelphia, Maryland pressed its claim in the sparsely inhabited lands west of the Susquehanna River.

After fifty years of failing to resolve the matter, Cresap was hired by Maryland officials to defend Lord Baltimore’s claim of land. For nearly eight years, Cresap and his followers clashed with area residents and local law enforcement officials. His enemies nicknamed him the “Maryland Monster.”

The armed phase of the conflict ended in May 1738 with the intervention of King George II, who compelled the negotiation of a cease-fire and established the border fifteen miles south of Philadelphia. The line, however, was not officially defined until British astronomer Charles Mason and surveyor Jeremiah Dixon completed surveying the now famous Mason–Dixon line in 1767.

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Resources

• Cresap’s War