From the Genuki website, information written in the 1820s.
"DANES DALE, in the parish of Great Driffield, and wapentake of Harthill; 3 miles NW. of Driffield. There are within one mile of this place a great number of Tumuli, amounting to about five hundred, which from time immemorial have been called " Danes Graves." History is silent concerning their origin, but it is highly probable that the Danes who appear to have had a fortified camp near Flamborough, may have issued from thence to ravage the country, and have fallen victims to Saxon valour. Each tumulus is three or four feet high, and from twenty to thirty feet in circumference at the base. Many of these ancient depositaries of the dead have been recently opened, and found to contain each a human skeleton, which from the dry calcareous nature of the soil has been kept in excellent preservation upwards of a thousand years."
These mounds, covered by the trees of an old plantation, may be seen in a little valley within the boundaries of the Lordships of Driffield and Kilham, in the East Riding of Yorkshire, nearly four miles due north of Driffield.
They measure from 1 ft. to 3½ ft. in height and 9 ft. to 33 ft. in diameter. The place has from time immemorial been called " Danes' Graves " and " Danesdale." Some accounts say there were originally 500 at least of these mounds; but on the Ordnance Map 197 is the number given. Their comparative preservation seems to be due entirely to the protection afforded by the old trees growing on them. Very probably they once extended, on two sides at least, beyond the boundary of the plantation into the adjoining fields, but there the plough has obliterated all surface trace of them. Many of them within the plantation have been more or less levelled, and some wholly obliterated by persons digging for rabbits ; while others have been frequently excavated at various periods by relic seekers and the otherwise curious, who have left no authentic account of their finds.
The first written record respecting these barrow is given by Leland more than 300 years ago.