John Loudon McAdam was born in Ayr, Scotland, at Lady Cathcart's house in Sandgate, on 21 September 1756. The McAdam's residence at Waterhead at that time was the home of Lord Carthcart at Ayr until 1760, when the family built a new residence and moved to Lagwyne. Lagwyne Castle, now in ruins, lies on the outskirts of Carspairn, Scotland, and was part of the property on the Waterhead estate. James McAdam had moved the family residence from Waterhead to Lagwyne because it was more accessible.
Shortly after the family moved into the new number in indonesia residence at Lagwyne, it burned to the ground. James and Susanna were on a business trip to Edinburgh when the Castle caught fire. A chimney fire is said to have started the blaze. John Loudon narrowly escaped the blaze only to be rescued by the family nurse.
James McAdam did not rebuild Lagwyne Castle and moved the family to Blairquhan, or sometimes called the White Lord's Castle, near Straiton. He rented the Castle to Sir John Whiteford. Whitesunset Castle has since been demolished and replaced by the present Blaiquhan Castle.
James' lifestyle and poor management of his business caused him to suffer many financial losses. His financial empire collapsed along with the Bank of Ayr, which he had co-founded. These financial setbacks forced James to sell the family's former Waterhead estate. The title to the property is unclear, but Waterhead eventually became the property of John McAdam of Grimmit, who purchased it on 21 January 1778.