1893 Sep 11. Born in Campbelltown, Argyll, son of Donald McLachlan, Maltster and Marion (nee Fisher)
1911 Census living with widowed mother in Campbelltown
1917 May 30 The undermentioned from an Officer Cadet unit to be 2nd Lts. Duncan Galbraith MacLachlan
1918 Nov 30 The undermentioned 2nd Lts. to be Lts.: — 3rd R. Highlanders D. G. MacLachlan.
1920 Apr 1. The undermemtioned relinquish their commns.3rd R. Highrs. — Lt. D.G. MacLachlan, and retains the rank of Lt.
1920 Aug 13. Joined ADRIC with service no 206. Posted B Coy in Tipperary.
1921 Jan 19 to 12 Feb on Leave
1921 Feb 4. Promoted Platoon Commander
1921 Jul 16 to 4 Aug Medical Leave
1921 Sep 12 to Oct 12. Medical Leave
1922 Jan 23. Discharged on demobiliation of ADRIC
1940 May 3. The undermentioned Lts. relinquish their rank on enlistment into the ranks of the Army: — D. G. Maclachlan (late R. High'ers (Spec. Res.)).
1941 Jan 9. Pioneer Corps The undermentioned to be Lts.: — Actg. Serjt. Duncan Galbraith Maclachlan (146812).
1942 Jun 25. The undermentioned Offrs. relinquish their commns. on account of ill-health. Lt. D. G. Maclachlan (146812) and retains the rank of Lt
1978 Died Henley, Oxfordshire.