The center's principal artifact is a 21 by 30-foot (6 by 9 m), two-story log slave pen built in 1830.
By 2003, it was "the only known surviving rural slave jail," previously used to house slaves prior to their being shipped to auction.
The structure was moved from a farm in Mason County, Kentucky, where a tobacco barn had been built around it.

It was reconstructed in the second-floor atrium of the museum, where visitors encounter it again and again while exploring other exhibits.
Passersby on the street outside can also see it through the Center's large windows.

The pen was originally owned by Captain John Anderson, a veteran of the Revolutionary War and slave trader.
Slaves from the area were transported from Dover, Kentucky to slave markets in Natchez, Mississippi and New Orleans, Louisiana; they were held in this pen for a few days or several months, as he and other traders waited for favorable market conditions and higher selling prices.
The pen has eight small windows, the original stone floor and fireplace.
On the second floor are a row of wrought iron rings (see photo at right) through which a central chain ran, tethering men on either side.
Male slaves were held on the second floor, while women were kept on the first floor, where they used the fireplace for cooking.

"The pen is powerful," says Carl Westmoreland, curator and senior adviser to the museum. "
It has the feeling of hallowed ground.
When people stand inside, they speak in whispers.
It is a sacred place.
I believe it is here to tell a story – the story of the internal slave trade to future generations."

Visitors to the museum can walk through the holding pen and touch its walls.
The first names of some of the slaves believed to have been held in the pen are listed on a wooden slab in the pen's interior; they were documented in records kept by slave traders who used the pen.

Westmoreland spent three and a half years uncovering the story of the slave jail.
Its authentication by him and other historians is considered "a landmark in the material culture of slavery."
Westmoreland said,
We're just beginning to remember.
There is a hidden history right below the surface, part of the unspoken vocabulary of the American historic landscape.
It's nothing but a pile of logs, yet it is everything.
The center's principal artifact is a 21 by 30-foot (6 by 9 m), two-story log slave pen built in 1830. By 2003, it was "the only known surviving rural slave jail," previously used to house slaves prior to their being shipped to auction. The structure was moved from a farm in Mason County, Kentucky, where a tobacco barn had been built around it.
It was reconstructed in the second-floor atrium of the museum, where visitors encounter it again and again while exploring other exhibits. Passersby on the street outside can also see it through the Center's large windows.
The pen was originally owned by Captain John Anderson, a veteran of the Revolutionary War and slave trader. Slaves from the area were transported from Dover, Kentucky to slave markets in Natchez, Mississippi and New Orleans, Louisiana; they were held in this pen for a few days or several months, as he and other traders waited for favorable market conditions and higher selling prices. The pen has eight small windows, the original stone floor and fireplace. On the second floor are a row of wrought iron rings (see photo at right) through which a central chain ran, tethering men on either side. Male slaves were held on the second floor, while women were kept on the first floor, where they used the fireplace for cooking.
"The pen is powerful," says Carl Westmoreland, curator and senior adviser to the museum. "It has the feeling of hallowed ground. When people stand inside, they speak in whispers. It is a sacred place. I believe it is here to tell a story – the story of the internal slave trade to future generations."
Visitors to the museum can walk through the holding pen and touch its walls. The first names of some of the slaves believed to have been held in the pen are listed on a wooden slab in the pen's interior; they were documented in records kept by slave traders who used the pen.
Westmoreland spent three and a half years uncovering the story of the slave jail. Its authentication by him and other historians is considered "a landmark in the material culture of slavery." Westmoreland said,
We're just beginning to remember. There is a hidden history right below the surface, part of the unspoken vocabulary of the American historic landscape. It's nothing but a pile of logs, yet it is everything.
National Underground Railroad Freedom Center