The chess pieces were found in a large dump of off-cuts near the foundations of a timber-framed building
Archaeologists have found two Medieval chess pieces made from antler during the final stages of a dig in Northampton town centre.
The excavation is at St John's Street, at the location of Northamptonshire County Council's new £43m headquarters.
Archaeologist Jim Brown said the pieces were "clear evidence" of demand for a "leisure product" in middle to late 12th Century Northampton.
The dig has now been completed and the finds will eventually go on display.
The larger piece was probably intended to be a bishop and is 60mm (2.3in) high, while the second piece was the top part of a king and is about 30mm (1.2in) high.
Mr Brown, from the Museum of London Archaeology, said the chess pieces were found among bone and antler off-cuts, and appear to been discarded during their manufacture.
The site was surveyed before building work can begin on a new council headquarters
He said: "They provide us with clear evidence of antler and bone working in the town, making something which is effectively a leisure product.
"It took quite a lot of effort to hand carve and finish these kind of things, so it's going to be something that you're paying the craftsman for.
"It's almost certain we will publish something about this material as it's of interest to researchers looking into history of board games."
The dig has previously uncovered malting ovens, fragments of cloth and a bread oven.
Work constructing the council headquarters begins in January.