The First Canadian Army was the senior Canadian operational formation in Europe during the Second World War.

The Army was formed in early 1942, replacing the existing unnumbered Canadian Corps

Canadian Corps (World War II)

The unnumbered Canadian Corps was the first corps-level military formation established by the Canadian Army during World War II. A four-division Canadian Corps had existed during the First World War...

, as the growing number of Canadian forces in the United Kingdom necessitated an expansion to two corps

Corps

A corps is either a large formation, or an administrative grouping of troops within an armed force with a common function such as Artillery or Signals representing an arm of service...

. By the end of 1943 Canadian formations in the UK consisted of three infantry divisions, two armoured divisions, and two independent armoured brigades.