The stone was taken from its position on Whams Road, near Flouch roundabout, in 2002 and the incident was reported to the police by a witness who saw it being taken away in a van.
However, despite locals believing it would never return, it ended up on eBay last year before being tracked down by Barnsley Council conservation officers and local historians.
The local authority’s legal team stepped in and had the item taken down, before it was returned to the council’s possession and stored at Elsecar Heritage Centre.
Since then it’s been lovingly restored by Christine Minto, founder of The Milestone Society, and her son Phil.
Now back in position, vandal-proof bolts have been used to attach the metal to the stone and it has been set in concrete to deter any would-be thieves.
Christine told the Chronicle: “In March 2002 I took a photo of this milestone but later that year it disappeared.
“These types of milestone were set up all over the old West Riding in 1893/94 from south of Rotherham, over the Pennines into Saddleworth, as far north as Sedbergh and across towards Harrogate.
“Late last year one of society’s members spotted it on an auction site - it is Grade II-listed, so the auction house was informed and the item had to be withdrawn from sale.
“I went to Whams Road, armed with my old photograph, to see if its original site could be identified.
“Last November, at Elsecar, son Phil and I stripped off all the old paint, applied red oxide, two layers of paint and then the legends in black.
“The council’s senior conservation officer, Tony Wiles, eventually sourced a good piece of stone which was shaped to match the metal attachment.
“Last month it was reset by the wall just north of the last house on Whams Road at its site.”
Such waymarkers - which were used to ascertain distances to locations by travellers - are fast disappearing and just 9,000 are thought to survive in the UK.
Coun James Higginbottom, cabinet spokesperson for environment and highways, added: “This is a fantastic example of working with our residents and protecting our borough for future generations.
“The moment we were informed that a missing milestone was being sold, we took immediate action through our legal services and had the item taken down from an auction website.
“We’re delighted that the milestone was recovered, restored and returned to its rightful place.
“We’re incredibly lucky that Barnsley has a rich history and heritage, and its assets are there to be enjoyed by everyone in the borough and those visiting Yorkshire.
“This is an example of where we stopped a piece of our history from being taken away from us and I’d like to thank everyone involved.”