That distinction was not always so tangible, particularly in the decades when slavery was common throughout the commonwealth, a period that ran from colonial times through the 1830s. Locally, slaves could be found in Dauphin, Cumberland, York, Lebanon, Lancaster, Adams, and Perry counties some fifty years after the commonwealth passed legislation to end it. Slavery was coming to an end by that time, though, and slaves mixed freely with free blacks in the larger towns of all these counties. Toward the end of that era, Harrisburg was beginning to gain a sizable free black community, and only then could be seen as a possible destination for freedom seekers. Fugitives knew that they could count on their free brethren to provide food, shelter, new clothes, and most of all the anonymity that a large town could offer by allowing new arrivals to blend in with the African American populace. The local black community also secured housing and jobs for these new arrivals with local employers, and many persons who were formerly enslaved settled down in this welcoming town, to a newfound life of freedom. State laws friendly to fugitive slaves provided a degree of comfort, and the Mason-Dixon Line came to represent, to many freedom seekers, the line between freedom and bondage. The intervening counties of York, Adams, and Cumberland provided an extra buffer zone bordered by the Susquehanna River. That line of safety, delineated by the river, was temporarily erased, however, after the passage of the federal Fugitive Slave Act of 1850, when most of the guarantees against kidnapping and assurances of personal liberty were taken away by Congress. Liberty’s border was again in flux. Sometimes freedom and the lines that defined it were as difficult to see as the tiny dot of light at the end of Theodore Burr’s long wooden bridge.

Freedom on this day, particularly to the African American refugees that ventured onto the wooden floor joists of Mr. Burr’s most famous covered bridge, meant escaping the invading troops of General Robert E. Lee’s Army of Northern Virginia. The specific troops that threatened their liberty were elements of Brigadier General Albert Gallatin Jenkins’ Virginia Cavalry Brigade that had swept into Chambersburg the previous week and had since been terrorizing the countryside as they drew steadily closer. In front of the marauding southerners were Union soldiers in full retreat. On Monday, 15 June, fifty army wagons under the command of Colonel A. T. McReynolds rolled through Greencastle in Franklin County, a vestige of the scattered garrison of Brigadier General Robert Milroy in Winchester, Virginia. Milroy’s command, consisting of about 7,000 men, had been overrun by a Confederate force of more than 12,000 soldiers under the command of Lieutenant General Richard S. Ewell. Ewell’s Second Corps had been ordered to clear the Shenandoah Valley of all Union troops, which they did easily, in preparation for Lee’s planned invasion of Pennsylvania. Milroy’s garrison was outnumbered and in full retreat, attempting to reach Charles Town, Virginia, when a night flanking maneuver by Major General Edward Johnson’s division cut them off on the morning of 15 June. Union losses were more than 4400, including 2400 who surrendered, while the Confederates lost less than 300 men.¹⁷ McReynolds’ wagon train, the remnants of his garrison at Berrysburg, was driven by tired, battle-shocked men who had just barely escaped from Ewell’s encirclement, and who were desperately trying to reach Harrisburg. General Milroy had also escaped, and passed with some other survivors through Carlisle a week after the fiasco on the fifteenth, arriving in the county seat of Cumberland on Tuesday the twenty-third, just two days before this group of refugees reached the bridge. Their headlong and breathless flight had been triggered by the reports from the military men that Confederate troops were not far behind.¹⁸