66th (2nd East Lancashire) Division

The 66th (2nd East Lancashire) Division of the British Army was a second-line Territorial Force division, formed in 1914, which saw service on the Western Front during the later years of the First World War. It was reformed in 1939 as the 66th Infantry Division in the Territorial Army, but disbanded in 1940 without seeing active service in the Second World War.

The division was formed as a duplicate of the 42nd (East Lancashire) Division in 1914, composed primarily of soldiers from eastern Lancashire and the industrial towns around Manchester. After training and home service, it deployed to the Western Front in early 1917; its first major combat came in October of that year, at the Battle of Poelcappelle. In early 1918, it took heavy losses during the German Spring Offensive, and was withdrawn from the line and reduced to a cadre in order to rebuild. It returned to the front in time for the Battle of Cambrai, part of the "Hundred Days Offensive", and the Battle of the Selle. Following the Armistice, it was stationed in Belgium, where it was demobilised in March 1919.

The division was not reformed after the war, but was reconstituted as the 66th Infantry Division during the hurried expansion of the Territorial Army in 1939. It was active for slightly over a year before being finally disbanded in June 1940, having only seen home service.