The grave is on private land near Wingham NSW.
Manning River Times and Advocate for the Northern Coast Districts of New South Wales (Taree, NSW : 1898 - 1954), Wednesday 21 May 1902.
Road — Wingham to Kelvin Grove. Public Works Department, Sydney, 9th May, 1902.
Sir, — In reply to your communication, dated 3rd March, 1902, from Mr. Thos. Joyce, Hon. Secretary to the Dingo Creek Progress Committee, presented by you, relative to opening up of road through Mr. Johnstone's property, road Wingham via Ashlea to Kelvin Grove, I am directed by the Minister to inform you that he has approved of tenders being called for this work, returnable about the middle of June. I have, &c., J. Davis, Under-Secretary. J. Thomson, Esq., MP.
https://trove.nla.gov.au/newspaper/article/172471580 James Johnston's wife died in 1902. (They had married in Sydney in May 1845 and had 3 daughters). Harden is a long way from Wingham but the family liked the name due to links with home.
Goulburn Herald (NSW : 1881 - 1907), Wednesday 3 December 1902.
Harden, Monday. Mrs. Johnston, mother of Mrs. George Rogers, of Kelvin Grove died yesterday, aged ninety. Deceased was one of the oldest residents. She was a sister of the late Mr. John McCallum of Forest. Lodge, near Goulburn.
https://trove.nla.gov.au/newspaper/article/100498791Neil