 Mason-Dixon Historical Park is located on the banks of Dunkard Creek in an area where the creek crosses the border three times in less than one mile.The park grounds include Brown's Hill, the westernmost site from which Charles Mason and Jeremiah Dixon made astronomical observations during the original survey of the Pennsylvania–Maryland border in 1767.The creek is named for members of the Dunkard Brethren, a pacifist, nonconformist group of Christians who settled in the region during the 18th century and practiced baptism by immersion.