Keir House, listed category A, was originally Georgian, with additions in the period 1820 to 1831 by David Hamilton, further alterations between 1849 and 1851 by Alfred Jenoure assisted by William Stirling II (Architect) for Sir William Stirling Maxwell, between 1899 and 1901 by Sir R. Rowand Anderson, and further work and final developments carried out by Balfour Paul in about 1912 who was Anderson's partner and successor.
West Terrace, listed category B, was built by Sir R. Rowand Anderson between 1899 and 1901. He also designed a Sundial, listed category B, in about 1906. The Entrance Tunnel and Terrace, were built between 1846 and 1860 at the same as the Garden Seat was added. Both are listed category B. Three Bridges, all listed category B, were also constructed between 1849 and 1862. Two are footbridges over Home Farm Drive and the other is near the William Stirling Cenotaph. A circular Column, listed category B, made of open brick work, is sited at the east end of the Upper Terrace. The Wall, listed category B, enclosing the Woodland Gardens includes Slave Gateway, Gate and Stairs to Lodge Drive and Swan Gateway in the listing. The Walled Garden, listed category B, was built in about 1820 in the style of David Hamilton and gateways were added about 1850. The Screen Wall and its Pavilions, listed category B, were built between 1849 and 1862. Other features in the Gardens include another terrace with a Column of open brickwork, a small Fountainhead, made from boulders, a rustic Bridge, an Archway and a small Cascade. These are all listed B for the group. The Bathing House, listed category B, is a gothic building with a pointed arch and was built by Sir R. Rowand Anderson about 1893.
The Ice House, listed category B, was built in the early 19th century. The Water House, listed category C(S), was built about 1871. The Garden House and Stud House, listed category C(S), were built between 1849 and 1862 and the Garden House has additions by Sir R. Rowand Anderson dated 1904.
The Home Farm, listed category A, was originally by David Bryce and remodelled in 1858 by Jenource and Stirling. It is built around a central courtyard with three storey clock tower. The Lodge, listed category B, is dated 1861. The North Lodge, listed category C(S), is attributed to David Hamilton in about 1820. The South Lodge, listed category A, has twin Greek Doric column archways and was built about 1820, probably by David Hamilton. It was moved and re-erected when the motorway was constructed. Old Lecropt Churchyard, listed category B, has fine gatepiers and the wrought iron gates were added by Sir R. Rowand Anderson in the early 20th century.
The parkland falls into five areas. Four of these, to the south and west are managed as traditional grass parks, while Meikle Park is cultivated. In 1748 these areas were shown as small plots of pasture surrounded by woods but they were then transformed by agricultural improvement. The 1801 plan by Thomas White shows scattered trees and clumps throughout an extensive parkland with flowing lines of shelterbelts, woodlands and a curving driveway. Sir Henry Steuart of Allanton's gardener is thought to have assisted Charles Stirling, the laird's brother, to lay out the grounds in about 1817. The road was resited and the lodge constructed by David Hamilton and William Stirling II between 1820 and 1830. Sir William Stiring Maxwell continued the planting and enlarged the woodlands. Today many of the parkland trees remain with oak, lime and beech probably dating from the period 1790 to 1810 and copper beech and ash dating from the period 1860 to 1880. The layout of the main entrance to the site from the north and east was altered, and the lodge resited, to make way for the recent M9 construction.
Woodlands around Keir were probably extensive and valuable in the 1600's. Roy's map of 1750 shows a heavily wooded area west of the house. Most of the woods have been managed and a number replanted with conifers but originally some, such as Little Hill, would have been linked to the garden by woodland walks, and contained features such as the Icehouse and a Monument. The woodland south-west of the house and drive, around the Lower Glen, contains the ruins of the Cascade/Grotto and the Bathing House, dating from 1893.
These were originally laid out as 'The Green Terrace' in 1750 to 1760. These were developed by Sir William Stirling Maxwell between 1848 and 1856 around an old Spanish chestnut tree, thought to date from the early 16th century, which still survives although held together by chains. There is no known architect but the style is Spanish/Italian and may have been influenced by Sir William's familiarity with Spanish Art. James Niven assisted Sir William before 1866. Sir R. Rowand Anderson and his young partner, Balfour Paul, created further steps, terraces and fountains in the grand style in about 1905.
Today the pencil cedars trained up the face of the house, which were replaced in about 1950, are a particular feature of Keir. Extensive topiary, clipped yew hedges, a bowling green, a formal rose garden, striking herbaceous borders and the 1920 south- facing rockery are all characteristic of the terraces as they are today, and they are still embellished by architectural ornamentation dating from several periods. Planting has continued over the years during the occupation of Mr Archibald and Mr William Stirling and the gardens remain as a lavish tribute to their designers.