The sign on the Maryland line today says "Welcome to Pennsylvania," but in June of 1863, many Pennsylvanians didn't stick around to greet the Confederate Army of Northern Virginia.
As the soldiers moved up the Cumberland Valley and into Adams and York counties, many people fled.
"There were farmers trying to save their cattle. Everything from milk cows to their horses, they were trying to get them out of there," said Brett Kelley, curator of the National Civil War Museum in Harrisburg. "There were valleys up in the North where they would bring their livestock to hide them from the Confederacy."
"Some of them were determined to stay here and guard their homes, while others just wanted to get across the Susquehanna to safer lands like Lancaster and Lebanon," said Cooper Wingert, author of the book The Confederate Approach on Harrisburg.
Refugees poured into Harrisburg, and even the state government prepared to move.
"The state Capital was being packed up, and all of their documents - boxes and boxes, thousands of boxes of documents - were being packed up, ready to ship further east to stay out of the way of the Confederacy," Kelley said.
Confederate General Robert E. Lee issued orders for his soldiers to be on their best behavior. No stealing was permitted.
"Whatever they took, they were expected to pay for," Kelley said. "They were expected to pay for it in Confederate money, which was basically useless in the North, but they treated the civilian population relatively well, considering what a huge army it was."
But not when it came free slaves.
"There are a number of accounts of Confederates taking African-Americans here in Central Pennsylvania back into Virginia and down South, back into enslavement," Wingert said.
"It was definitely a very scary time for black Americans during that particular campaign," Kelley said. "Most had vacated the area as soon as they knew the Confederates were coming. Some were probably caught unaware, but the vast majority of them gave the Confederate army a very wide berth."