Various estimates have suggested that the peatlands of Scotland are a significant deposit of fixed carbon. However, these have been based upon rather imprecise estimates of peat depth. Using previously unused archived data, we have mapped peat depth across the country and then used these values to obtain an improved value of the total carbon stock within peatlands, as well as indicating their spatial distribution. We included peat deposits that occur in combination with other soils in soil map units other than 'blanket' or 'basin' peat. We obtained an area-weighted mean peat depth of 2.0 m, which is slightly shallower than previous estimates. Using values of bulk density and % carbon from the Scottish soils database, the total peatland carbon stock came to 1620 Mt, which represents 56% of the total carbon in all Scottish soils.