She was born on 16th December 1865 in Braidwood, a small village a couple of miles to the south of Carluke in Lanarkshire. Her father, John Somerville, the local joiner, had married Helen Meikle some seven years previously and Agnes was their first and only daughter. She had three older brothers, Robert, John and William and one younger, Thomas.
By the time Agnes was 6, John Somerville had moved his family to West Calder where his wife's family farmed. Agnes grew up in West Calder and in 1891, at the age of 25, she married William Gillon, a butcher, son of local grocer Robert Gillon. William had worked for his father for many years but had just branched out on his own that same year and set up his own butcher's business a few miles to the east in Currie.

The following year, William and Agnes had their first child, daughter Helen, and a son, Robert, followed two years later in 1894. By the time daughter Elizabeth came along in 1897, the family had moved to nearby Balerno, opening another shop there but keeping the one in Currie as well.
In August 1902 tragedy struck. William contracted double pneumonia and died at the age of 43. Agnes somehow managed to keep the business going and, in time, her daughter Helen and son Robert both became master butchers.
All went well until, in early 1916, Robert was called up to join the army. He applied for exemption on the grounds that his mother was a widow and he attended weekly markets and bought for the business which was the only business of the kind in Currie Parish. It was a certified occupation and he was indispensible to the business, he maintained. In March 1916, the local tribunal refused his application as there were not sufficient grounds to support the application.
Both Robert and his mother appealed the decision, Robert writing "I am in the service of my mother Mrs Agnes Gillon, Butcher, Balerno. She is a widow and I am her only son. She carries on the only butcher's business in the parish of Currie. I attend the weekly live stock markets and buy for and manage the business. I am claiming exemption on the grounds that I am indispensable to my mother's business and that I am one of the principal means of her support. She is not so able as formerly to attend to all the details of the business and without my help I consider the business would fall behind or would probably have to be given up which would mean not only an inconvenience to our community but a personal hardship to ourselves. I am also engaged in a certified occupation. Signed by me, Robert Gillon."
Agnes echoed Robert's sentiments "I am a widow carrying on the only butcher's business in the Parish of Currie. Robert Gillon, for whom I am claiming absolute exemption, is my only son. He attends the weekly live stock markets and buys for and practically manages the business. As I am not so able as I used to be to give my full attention to the business, it would be very serious hardship if I did not have his help. In fact as it is simply impossible in these times to get a substitute, it is a question whether without his assistance I could carry on the business and then financial loss and straitened circumstances would follow. I do not know whether I could get any other to do the work my son Robert does. I also claim exemption on the grounds that he is engaged in a certified occupation."
The appeal was dismissed by the tribunal on the grounds that the slaughterman and van salesman in the same business were already exempt and it "should not be impossible for the applicant to make other arrangements for the carrying on of the business, in view of the close proximity of the Edinburgh Slaughterhouse." They also felt "that it is more expedient in the national interests that the attested man should be employed in military service than be engaged in his present occupation."

So Robert joined the army and on 14th October 1916 he wrote out his soldier's will, leaving his worldly goods to his mother. He was subsequently shipped out to France to serve with the King's Own Scottish Borderers as a Private in 2nd Battalion. A year later, on 4th October 1917, he died at Zillebeke in Belgium, at the age of 23. Zillebeke lies just to the east of Ypres and was very heavily bombarded by German artillery.
In all, 45 Balerno men fell in the First World War from a village listed as having a population of 674 in 1912.
Although she must have been devastated by the loss of her son, Agnes again managed to keep the business going aided by daughter Helen Meikle Gillon, who never married. She had another daughter, Elizabeth McCarter Gillon [1897-1968], who married her cousin John Ferguson Watson.
Agnes died in Balerno at the age of 76 was buried alongside her husband.