In 1732 Charles Carroll of Maryland received a grant of 5000 acres of land in present Adams County, Pennsylvania, from the authorities of Maryland. Soon after, a survey of that land, known as “Carroll’s Tract” or “Carroll’s Delight,” was conducted. At that point in time there was still some dispute over the location of the boundary between the two states. A temporary line was agreed upon in 1739, and a more permanent line (very near that temporary boundary) was surveyed by Charles Mason and Jeremiah Dixon during the 1760s. And even though it was established that Carroll’s Tract was in Pennsylvania, an agreement was made that Marylanders would retain their rights to the lands previously granted to them. But it is important to note that at an early date the people settling in this area knew they were in Pennsylvania. According to Charles H. Glatfelter, the most respected of local historians, “the widely held and long persisting notion that until many years later people did not know where the boundary line was and that it shifted from time to time has no basis whatsoever in fact.” [excerpt]
Smith, Timothy H.
"A History of the Early Fairfield Town Lots,"
Adams County History: Vol. 19
, Article 3.
Available at: https://cupola.gettysburg.edu/ach/vol19/iss1/3