Foulis (Gaelic "Fo-glais" meaning a streamlet) has by tradition been associated with the Clan Munro since early in C11th. By written evidence it was acquired by a Munro Chief in the early 14th century, the present Chief is the 33rd of that name. Whilst the plans of the original Castle are long since lost, the grounds still contain the site of an 11th century Mott - (a man made mound topped by a wooden palisade) and within the Castle itself the remains of a medieval keep can be found.

The present elegant Georgian E-plan house built on the foundations of the much earlier and altogether different defensive Castle, dates from the middle of the 18th century.  Discoveries during improvement works over the past fifty years indicate that the Castle was probably at some time a fortified tower house set within a curtain wall with smaller defensive towers built in the angles of the rectangular enclosure. The base of the present tower and part of the courtyard buildings have been dated to between 1450-1550 evidenced by four inverted key-hole gun-loops in the vaulted ground floor of one of the courtyard pavilions, before 1450 only in the grandest of buildings, and by 1550 giving way to much wider bell-mouthed ports. The most likely builder being John Munro, 11th Laird (1437-90).

In 1754, after a sacking at the hands of the Jacobites in 1745/6, the then Chief, Sir Harry Munro of Foulis (1720-1781) who succeeded his father, Sir Robert, (1684-1746) killed at the Battle of Falkirk, received £5,000 compensation from the Hanoverian Government out of the forfeited estates of the Earl of Elcho and immediately commenced tearing down much of the old Castle to rebuild it largely in the form we see today. Undoubtedly influenced by his time at Leyden University in Holland and by the neo classical style popular in the mid to late C18th, Sir Harry kept parts of the old work where he could not, without vast expense completely rebuild, and the symmetry of his new house was forced to fit the old foundations. This is particularly apparent at the back of the house where the tower is not central to the courtyard and the much older East Wing is considerably narrower than the later West Wing.

The main entrance in Sir Harry's day was to the rear of the present house served by a single external flight of stairs from what must have been a very busy courtyard with it's service quarters and stables. At the time the Castle straddled the main coach road running North and South but after his father's death in 1781 Sir Hugh Munro (1763-1848) became fed up with this intrusion on his privacy and ordered a new road to be constructed in a great sweeping curve half a mile to the South of the Castle where it remains to this day. 

Sir Harry caused the pedimented central pavilion with it's armorial panel of 1777 in the front facade to be brought forward to create a new doorway at ground level and probably formed the larger and more dignified entrance hallway by throwing the original inner stair hall and the central room in the south front into one by removing the entire five storeyed loadbearing wall at the front of the tower, replacing it with stout timber beams which he hoped would both carry flooring and ceilings across the increased span as well as support the elegant stone staircase leading to the third and fourth floors (an RSJ now does the job). The front of the tower room which was his library he reconstructed with light weight timber and impregnated sailcloth painted to match the external render of the Castle.

At Sir Harry's death in 1781 the house was still unfinished and it was his son Sir Hugh who opened up a central window on the second floor of the front (south) elevation to form the present main entrance doorway and built the elegant double external staircase, the railings for which were supplied in 1797. The courtyard was completed by 1799 and final detailing finished by November 1802 when Sir Hugh with his wife and young daughter Mary moved in. But tragedy struck the following August when Lady Munro together with two of her maids was drowned whilst batheing in the Firth just below the Castle.

Consumed by grief and attacked through the courts over the supposed illegitamacy of his daughter and therefore her right to succeed by ambitious cousins, Sir Hugh left Foulis for good and the contents were sold in 1826. The House was then abandoned and only occasionally let partially furnished to shooting tenants until the present Laird's great grandfather Sir Hector (1848-1935) and his young family took up residence in the 1880's after some very modest improvements including the instalation of a single bathroom on the third floor and a WC tacked onto the back of the West Wing. Fortunately, due to the relative impoverishment of the family caused by the litigation with Sir Hugh, the Castle escaped any major excesses during the Victorian era with only these few minor additions and alterations which have long since been removed.

Little other than redecoration was done in the ensuing 90 years. The Castle facilities were considered to be far too primitive for it to be requisitioned during the Second World War when other houses in the area were taken over by troops training for the invasion, and it was only partially wired for electricity shortly thereafter. The roof leaked and a series of buckets, pots and pans caught the drips. Foulis was one of the first houses in Ross & Cromarty to receive a grant from the newly formed Historic Building Council for Scotland (now Historic Scotland) when it was re-roofed in the 1950's.

Further major restoration phases were undertaken in the 1970's and 1980's and it is now once more a comfortable family home. However, as with all buildings of it's size and age, restoration, maintenance and the demands of modern lifestyles continue to be a constant challenge.