There does not appear to be any plan of Huntingdon Castle, that is, of the earthworks known as Castle Hill, which still are seen; and as they are extensive and partly included within a private garden, a mere handsketch is scarcely practicable. The position is a fine one. The Ouse, here deep, broad, and sluggish, in its way from Bedford and Eaton to the Fens, recedes from the higher land to the northward, and makes, between Huntingdon and Godmanchester, a bold curve to the south; thus enclosing a grand circle of meadow about half a mile in diameter, and now used as the racecourse. Along the northern edge of this breadth of sward flows the Alconbury brook, a considerable watercourse, which skirts the foot of the high land, and joins the Ouse opposite the Castle Hill, and just above the bridge by which the Ermine Street is carried across the river. Here, upon the edge of the high land, and protected from the south by the river and the brook, and the low and formerly impassable levels beyond them, are the ancient earthworks, which, though partially levelled, and reduced both in height and depth, and traversed by a road and a railway, are still very considerable, and form a remarkable feature in the view of the town from the south. In general outline the work is rather a circle than a square, and about 180 yards in clear diameter. The outer ditch, which is included in this measurement, encircles two-thirds of the whole, communicating at each end with the brook, which thus completes the investment. Upon the western margin of the area thus enclosed, and projecting boldly into it, is a large mound, the flat top of which, now crowned by a neglected mill, is 100 feet diameter, and about 30 feet high above the inner platform, and 40 feet or more above the country outside. This mound, which was the citadel of the work, had its proper surrounding ditch, which at the outer face was identified with the main ditch, but elsewhere cut off the mound from the general area of the fortress. This remainder, which, by the indentation of the mound and ditch cutting out a huge cantle, was converted into a sort of crescent, was defended along its outer edge by broad and high banks of earth, perhaps 20 feet above the contained area, and 30 feet or 40 feet above the circumscribing ditch. The railway passes east and west, close south of the mound, and cuts off a part of the work; the road passes north of the mound; and north of this a close fence shuts off from the visitors a part of the earthwork. The entrance was on the east, or town side. Towards the west, outside the ditch, is a natural elevated platform, which, at 100 yards distance, terminates in a steep slope, and which may have been a part of the defences, or perhaps a safe penfold for cattle. There was a mill mentioned in Domesday, upon the river below the castle. There is now no trace of masonry above ground, but the earthworks look as though they had been built upon.