The site of this castle or tower house is on level ground about a mile east of Sorbie village and five miles south of Wigtown. 

It does not, at first glance, seem a strong one but it is built on an artificial defensive mound, allegedly the remains of an early Pictish fort, and amidst marshy ground - for the name, Sourby, meant a dwelling amid swamps. This mound is now so closely overgrown with trees as to make both it and the castle scarcely decernible from any distance. The fortalice itself, while possibly imcorporating more ancient work, dates mainly from the late 16th and early 17th centuries, and though long ruinous, ivy-grown and neglected, in now being given some attention. 

The present tower or, as it was called in the Middle Ages, "The Place of Sorbie" was built around 1550-1575 and was occupied until 1748 since when and until recently it has been neglected. 

On the grounds close by is a mound which MacGibbon and Ross mention in their work, "The Castellated and Domestic Architecture of Scotland". This mound may well be the one on which the Viponts erected a wooden structure of the Norman type. In 1983 the Archaeological Department of Glasgow University carried out a "dig" at the motte and found shards of pottery identified as from Bordeaux and dating to around 1250. They also found pieces of coins of Henry III of France 1574-1589. Also on the grounds, traces of the base of a flying bridge were found such as the one depicted in the Bayeux Tapestry and there is a fine cobbled road buried which runs east from the existing castle courtyard. 

This is an L-shaped building, more lofty and commodious than many of its kind. It rises to three storeys and has an attic in the main block. The wing is a storey higher and ends in a gabled watch-chamber. There is no parapet nor walk. A tall stair-turret rises within the re-entrant angle above the first floor level. The bottom corbel of this turret is carved in the shape of a human head. There have been angle-turrets at the corners now reduced to their corbelling. Unfortunately much of the dressed stone of the windows has been torn out. 

The entrance is in the usual position within the re-entrant and is surmounted by an empty panel-space. The door was defended by no fewer than three draw-bars the deep sockets of which remain. The basement consists of four vaulted apartments. The kitchen occupied the north end of the main block and had an enormous arched fireplace in the gable 17 feet wide y 5 deep. There is a small window at one end and an aumbry at the other. Two vaulted cellars filled up the rest of the main block. Underneath the main stairway in the wing is another small vault, possibly used as a pit or prison. The main stair is handsome, squared scale-and-platt, which is unusual. It rises only to the first floor above which ascent is made by the turret stair. The Hall on the first floor was a fine apartment 27 by 17 feet with a large fireplace in the east wall. The flue is carried up in the large chimney-stack which abuts the stair-turret. It has two mural chambers in the thick north gable which also contains the huge flue from the kitchen fireplace and three small aumbries from elsewhere. Above was the usual sleeping accommodation.