'Round-up' was a US plan for a major Allied landing in German-occupied northern France (1942).
The plan was developed at the instigation of General George C. Marshall, US Army chief-of-staff, by Major General Dwight D. Eisenhower, then head of the US Army’s strategic planning department, and was presented to President Franklin D. Roosevelt on 1 April 1942.
In basic terms, 'Round-up' was conceived as the middle stage of a three-phase strategic offensive against Germany. The first phase was 'Bolero', which envisaged the build-up of US forces in the UK so that by April 1943 some 30 US divisions (including six armoured) were to have been delivered across the Atlantic together with the appropriate strategic and tactical air formations delivered in 'Sickle' (ii). The successful implementation of 'Bolero' would be followed on 1 April 1943 by 'Round-up', in which 45 infantry and three armoured divisions (30 US and 18 British) would begin to land (six divisions supported by airborne forces in the first wave) between Le Havre and Boulogne with the object of taking a sizeable beach-head that could be reinforced at the rate of 100,000 men per week to secure a lodgement running from Deauville to Calais via Paris, Soissons, St Quentin and Arras, but extended later to include Angers. The third phase of this US plan would be 'Sledgehammer', to be launched on 15 September 1943 to take Cherbourg and the Cotentin peninsula.
The British were not impressed with 'Round-up' which, they felt, had no strategic objective other than the obtaining of a lodgement, faced severe terrain problems in the landing phase, and would be opposed by Generaloberst Hans von Salmuth’s powerful 15th Army, a formation which had received favoured treatment in the supply of men, weapons and other matériel because of the very contingency the Americans were now advocating.
By August 1942 'Sledgehammer' had been abandoned and 'Round-up' modified to include 27 US and 21 British divisions. By November 1942, at the time of the 'Symbol' conference in Casablanca following the successful implementation of 'Torch', 'Round-up' was planned round a force of 30 divisions (including six armoured), but was cancelled at this conference in favour of a British-sponsored plan for the opening of hostilities against Italy with the 'Husky' (i) landing in Sicily followed by landings on mainland Italy.
It is worth noting that the British were eventually as reluctant about a total abandonment of 'Round-up' as they had initially been to support it, but in November 1942 Eisenhower told Prime Minister Winston Churchill that no major operation on the north coast of European continent could be carried out before 1944.
The briefings about the 'Round-up' plan served also to bring Eisenhower’s organisational and diplomatic skills to the attention of senior civil and military leaders in the USA and UK, launching his rapid climb to the position of Supreme Allied Commander, Europe.
'Round-up' included 'Sledgehammer' and its later 'Roundhammer' development, and also 'Superhammer'. Lieutenant General F. E. Morgan incorporated some elements of the plan into the earliest version of the plan which was eventually developed into 'Overlord'.