High Elms Manor is a grade II listed[1] Georgian country house located near Garston in Hertfordshire, England.

[2] In the post-World War II years the house was a rehabilitation centre, but it later fell derelict.

In the 1990s an American named Sheila O'Neill bought and restored it and it was used by her as a Montessori School until her death, and then subsequently by her daughters, who have now put it on the market.

He appears to have purchased the estate in the early 1800s and either built High Elms or made very substantial alterations to a small existing building.

His father was Sir Henry Cavendish of Doveridge Hall in Derbyshire and his mother was Sarah Bradshaw, who later became Baroness Waterpark.

John Ryley bought High Elms soon after this and he and his wife Charlotte remained there until he died in 1845.

The 1851 census shows that he and his wife Dora were living on the estate and states that Arthur was a magistrate and distiller.

He was educated at Cambridge and graduated in 1834 after which he was called to the Bar and for many years practiced as an Equity Barrister and conveyancer.

[17] After Robert came to live at High Elms, he became Chairman of the Quarter Sessions at St Albans in 1867 and was made a deputy lieutenant of the County in 1874.

His father, James Watney, Jr., was a member of Parliament and a wealthy brewer who owned the firm Watney & Co, Ltd. Claude was educated at Eton and Oxford University and then entered the family business where he rose to become Director in 1898.

One journal mentioned that Claude owned a Pipe car and was an all-round sportsman whose horses were famed for their mettle and speed.

The article also mentioned that Ada Watney owned a Pipe, a Panhard and a Mercedes and was one of London's best known lady motorists.

In 1896 Walter married Howard's sister, Clara Louisa Hollingsworth and the couple had seven children (Molly, Kathleen, Stafford, Christine, Helen, John & Jim).

Clara retained ownership of Garston Manor until 1932 when she put the house on the market.

[25] Colonel William Hilton Briggs and his wife Doris (see photo at right) were the next residents of Garston Manor.

During the war years the property was heavily defended with "pill" boxes and fortified trenches and three large air raid shelters were built, however there seems to be no record of occupation by presumably one of the services during this period.

The manor was used as a film location for various series and movies such as: Nancherrow, Second Sight with Clive Owen, Longitude with Jeremy Irons, Madame Bovary, The Hoobs by Jim Henson, photo shoot for Daily Mail, The Last Client, Featherboy with Sheila Hancock, Combat Sheep – Baby Cow Productions, Ultimate Force with Ross Kemp, Midsomer Murders (used three times), The Schartz Metter Klume Method, Rosemary & Thyme ("Enter Two Gardeners"), The Thieving Headmistress with Pauline Quirke, Chucklevision with the Chuckle Bros., Clandestine, EastEnders, Holby City (used twice), Little Miss Jocelyn, Invisible Eyes, Love at First Sight with John Hurt and Phyllida Law, In Clear Sight, and Morgana.

The official renaming as "High Elms Manor" by the Mayor of Watford was shown on the programme, who cut the ribbon amidst a celebratory tea party.

Mrs Watson encouraged Mrs O'Neill and three of her four daughters, who taught at the school and still live in the house with their families, to develop their weddings and events business to generate the extra income needed to maintain the house.