Circa 1424-1624 with 5 building periods. 1424-1437 building of the N, E, and S ranges with main entrance to E; 1437-1488 W range probably begun by James III; 1488-1513 range to W built and remodelling of older ranges by Nichol Jakcson, 1502-1512 succeeded by Stephen Balty (or Bawte); 1534-1541 main entrance moved to S, improvements to S range and interior by Thomas Fransh (or Franssh); 1618-1624 rebuilding of N range by William Wallace. Square-plan castle with central courtyard and taller flush square corner towers, 5-storey N range, 3 storeys to S, E, W ranges, corbelled and crenellated parapets, roofless. Cream sandstone rubble and ashlar dressings.
S RANGE: S (ENTRANCE) ELEVATION: single-storey projecting porch with corbelled parapet, segmental-arched entrance flanked by circular angle towers. Gun-loops to towers and to left at ground. Windows at 1st and 2nd floors above and to left of porch. 5 tall round-headed windows lighting chapel at 1st and 2nd floors to right. Tower to left (W) with window to each floor; tower to right with door to left and window to each floor.
N (COURTYARD) ELEVATION: 5 near symmetrical bays flanked by curved turnpike stair to corners; base, string and cill course. Moulded round-arched entrance 2nd bay from left with image niches above between 1st and 2nd floors and tripartite windows with square-headed cusped lights to right and to 2 bays to left. Symmetrical fenestration at 1st and 2nd floors with square-headed windows with round-arched and cusped lights, tripartite windows with round-arched and cusped lights, tripartite to 2nd and 3rd bays from left and 4-light to 1st, 4th and 5th bays.
E RANGE: E elevation: round-arched entrance high above ground to centrre, linked to ruins of 3 round towers to N (remains of barbican) by Flying Buttresses. Above entrance, high relief carving set in basket-arched frame of royal arms supported by 2 angels with a 3rd angel above flanked by long vertical slots (for drawbridge mechanism) and set in basket-arched recess. Centrepiece franked by long canopied image niches. Irregular arrangement of narrow lights to right with bipartite window to outer right. 6 square-headed windows to top storey (lighting great hall) and large rectangular window with moulded reveals to their left.
W (COURTYARD) ELEVATION: round-arched entrance with hoodmould off-centre left, 3 canopied niches above and 3 angels with outstretched wings overhead, deep hoodmould with soffit cusps and naimal head label stops. Row of 7 small lights between and to right of niches (lighting passage for operating portcullis). Heavily moulded basket-arched/ogeed entrance at 1st floor to left (former door to great hall). 6 symmetrical moulded round-arched windows to upper storey. Curved turnpike stairs to angles at right and left.
N RANGE: 5-storeys.
N ELEVATION: near-symmetrical, 5-bays to centre with small square-headed windows to basement, canted window with stone roof to outer right. square-headed tripartite windows with stone mullions and transoms to 1st, 2nd, 3rd and 4th floors. E corner tower: loop window at basement, tripartite and double transomed window to 3rd floor, tripartite window to upper storey, corbelled course, set-back crow-stepped gabled wall with apex stack above. W corner tower: group of 3 oriels at 1st floor (2 to outer right in ruins), cusped narrow windows, steeply pitched stone roof to left. Bipartie window above with window to upper storey.
S (COURTYARD) ELEVATION: 5-storeys reducing in height with each storey, 7 symmetrical bays with canted stair tower to centre; string course to each floor, pedimented square-headed windows with semi-circular pediments to upper storey windows (except ground floor), corbelled and moulded stepped crenellated parapet. Stair tower with roll-moulded doorpiece and window above, window to each floor (window above window to 3rd floor), moulded cornice. Flanked by small windows (not ground floor) with alternating triangular and semi-circular pediments, flanked by loop windows, regular fenestration elsewhere.
W RANGE: W ELEVATION: lower central portion flanked by taller angle towers, asymmetrical arrangement of windows and loop windows.
E (COURTYARD) ELEVATION: asymmetrical arrangement of windows to left, moulded window with semi-circular pediment to centre, window above. Segmental-headed door to right with 2 moulded round-arched windows above and to upper storey with 14-light horizontal ladder window between. Curved turnpike stair to angles.
INTERIOR: E, S and W ranges have barrel-vaulted under-crofts. E range: great hall at 1st floor with barrel vaulted minstrels gallery and magnificent fireplace with tripartite hearth divided by clustered shafts with foliate capitals and broad hood with decorated bases for statues.
S RANGE: chapel at 1st floor.
W RANGE: King's suite at 1st floor, hall with 15th century fireplace with hood and paired shafts. Bed-chamber and rib-vaulted roof. Queen's suite on 2nd floor.
N RANGE: long gallery/dining hall at 1st floor.
FOUNTAIN: circa, 1538. Elaborately carved hexagonal well. Cream sandstone ashlar (badly weathered). Plain plinth, 2 off-set decorated stages with figures to angles, decorated flying buttresses between stages, mask gargoyles above crowned by circular decorated cuppola.