Askham Bog is small area of peat bog and Site of Special Scientific Interest situated within the Vale of York in North Yorkshire, England. It lies to the south-west of York, north of Copmanthorpe and near Askham Richard and Askham Bryan. It is regarded as one of the most ecologically diverse sites in Northern England. During the 2010s, a development of 500 houses was proposed for the edge of the bog on the outskirts of York city, but this was overturned in 2020.