21st Division was the first of the six created for the Third New Army which had been authorised under Army Order 388 on the 13th September 1914. After the debacle in the trenches and mud at Loos in September 1915 they would go on to be one of the finest British Divisions of the Great War. By the end of World War One they had suffered 55,581 killed, wounded and missing, being the highest number of casualties suffered by a New Army division.
There exists no Divisional History of 21st division written since the war, though some regimental and battalion histories exist. This site hopes to correct that, charting the progress from New Army Division to battle hardened unit by the wars end. From its origins and unfair bad name it gained at Loos, it would by virtue of the Somme, Arras, 3rd Ypres,Cambrai, German Spring Offensives and the 100 days gain a reputation as one of the finest divisions in the BEF.