The glass furnace sieges and the structures associated with annealing furnace flue of the Bolsterstone Glass House, Stocksbridge, Sheffield (φ= 53.47°, λ= -1.59°), have been dated using archaeomagnetic techniques. The lintels over the annealing furnace flue, were found to have not been heated sufficiently to reset the magnetisation, but nine samples from the footing of the main arch structure were significantly heated. These produced a direction (corrected to Meriden) of declination= 338.2o, inclination= 70.9° (α95= 1.8°, K= 326). This indicates that the best estimated date for the last heating of this structure is AD 1840 (95% confidence interval – AD 1800–1870). This date may accord with the later time of use of the structure for pottery production. Samples from the remains of the glass furnace sieges, and the possible glass moulding floor (ie, silica-rich samples containing glass) were collected from an excavated pit inside the present building. Three silica-rich samples and seven reddened sandstones together produced a mean direction (corrected to Meriden) of declination= 349.7°, inclination= 73.5° (α95= 1.5°, K= 347). This suggests that the best estimated date for the last heating of the sieges and use of the moulding floor is AD 1710 (95% confidence interval – AD 1680–1730).