This marker is the one that was featured in the 1971 National Geographic Magazine about Cumberland Gap, Kentucky.
According to Street View images from 2018, the marker is either gone or the top piece is missing. In 2009, it was still intact.
In a discussion about the sign on facebook, the person who lives across the road claimed: “I’ve been talking about restoring that sign for years. It’s a landmark. The tree company messed it up when they came through and cleared the side of the road for the electric company. That’s when they moved the power lines outta the mountains a there and put them on the side of the road. I painted that sign 6 times I think when I was a teenager.”