Few people realize that surveying for the Mason-Dixon Line started at a tiny house on the southern edge of Philadelphia, the AP reports.
The house is long gone, but its location was recently discovered by group of Pennsylvania college students paging through centuries-old property records. State officials approved a historical marker for the site last month.
The finding comes as the nation marks the 150th anniversary of the start of the Civil War. The Mason-Dixon Line has become synonymous with the divide between North and South, but that obscures its true origin.
Charles Mason and Jeremiah Dixon began their survey a century earlier to settle a border dispute between Pennsylvania and Maryland.
The 250th anniversary of the Mason-Dixon Line is in 2013.