All units of the size of an infantry battalion, cavalry regiment, artillery brigade and above were obliged to maintain a record of its movements and activities. These records are called war diaries.
Most of the diaries still exist and are held at the National Archives in series WO95. Some regimental museums have copies or transcripts. A few regiments, museums and individuals have made transcripts available online; there are some extracts on the Long, Long Trail.
An extract from the diary of the 15th (Service) Battalion of the Royal Irish Rifles. This is held at the National Archives as document WO95/2503. Crown Copyright. This is a typical entry, describing locations and events. Officers are named.
The National Archives has scanned some of the diaries and some can now be downloaded at the Documents Online section of their website for a small fee.
The diaries vary in the degree of detail they describe. Most do not mention men of the "other ranks" very much, if at all. Officers are regularly mentioned by name. Some diaries include added operational reports, signals, maps, casualty lists and other documents. They are an exceptional resource for determining the details of the activities of a given unit.
An extract from the diary of the 4th Battalion of the King's Royal Rifle Corps. This is held at the National Archives as document WO95/2843. Crown Copyright. An example of a casualty list included with the diary: gold dust for a researcher!
War diaries on this site
There are extracts from war diaries on the Long, Long Trail: diaries
War diaries on other websites
When we find a reliable transcript of a war diary we place a link to it on the relevant regimental page on the Long, Long Trail.
Canadian and Australian war diaries - including those of British units serving under Canadian or Australian formations - have been digitised and can be found at the links shown opposite.