Created on 1 November 1940, the division was formed by taking two brigade areas (31st and 39th) from the existing 7 Anti-Aircraft Division in North East England, together with a newly formed brigade (62 Brigade), and giving it responsibility for the air defence of East and West Yorkshire and the Humber Estuary.
On re-organisation of Anti-Aircraft Command in October 1942 the division was merged with 2 Anti-Aircraft Division to form 5 Anti-Aircraft Group based at Nottingham.
HQ York
Order of Battle 1940–41
| 31 (North Midland) Anti-Aircraft Brigade – HQ York: responsible for West Yorkshire |
| 87 Heavy Anti-Aircraft Regiment – joined by May 41 |
| 38 Light Anti-Aircraft Regiment (part) – to 2 Anti-Aircraft Division by May 41 |
| 71 Light Anti-Aircraft Regiment |
| 43 (Duke of Wellington’s) Searchlight Regiment |
| 49 (West Yorkshire Regiment) Searchlight Regiment |
| 54 (Durham Light Infantry) Searchlight Regiment |
| 39 Anti-Aircraft Brigade – HQ RAF Digby: responsible for airfields and Humber Estuary |
| 62 (Northumbrian) Heavy Anti-Aircraft Regiment |
| 91 Heavy Anti-Aircraft Regiment |
| 39 Light Anti-Aircraft Regiment |
| 40 (Sherwood Foresters) Searchlight Regiment |
| 46 (Lincolnshire Regiment) Searchlight Regiment – to 7 Anti-Aircraft Division by May 41 |
| 84 Searchlight Regiment |
| 62 Anti-Aircraft Brigade – responsible for Leeds and Sheffield |
| 75 (Home Counties) (Cinque Ports) Heavy Anti-Aircraft Regiment |
| 96 Heavy Anti-Aircraft Regiment |
| 117 Heavy Anti-Aircraft Regiment – new regiment formed in Dec 40 |
| 59 Light Anti-Aircraft Regiment – new regiment formed in Oct 40 |
| 2 Anti-Aircraft Z Regiment – new divisional unit formed in Sep 40 |
Order of Battle 1941–42
| 31 Anti-Aircraft Brigade |
| 12 Heavy Anti-Aircraft Regiment – from War Office Reserve Aug 42 |
| 87 Heavy Anti-Aircraft Regiment – left Anti-Aircraft Command Jun 41; later to Eighth Army |
| 128 Heavy Anti-Aircraft Regiment – from 62 Anti-Aircraft Brigade Aug 42 |
| 71 Light Anti-Aircraft Regiment – to 65 Anti-Aircraft Brigade Jun 42 |
| 114 Light Anti-Aircraft Regiment – from 4 Anti-Aircraft Division Jun 42 |
| 30 (Surrey) Searchlight Regiment – from 5 Anti-Aircraft Division Oct 41; to 11 Anti-Aircraft Division Jan 42 |
| 43rd Searchlight Regiment |
| 49th Searchlight Regiment |
| 54th Searchlight Regiment |
| 39 Anti-Aircraft Brigade |
| 62 Heavy Anti-Aircraft Regiment – to War Office Control for Operation Torch Feb–Mar 42 |
| 91 Heavy Anti-Aircraft Regiment – left Anti-Aircraft Command May 42; later to Middle East Forces |
| 113 Heavy Anti-Aircraft Regiment – from 2 Anti-Aircraft Division Mar 42; to 65 Anti-Aircraft Brigade May 42 |
| 152 (Mixed) Heavy Anti-Aircraft Regiment – from 62 Anti-Aircraft Brigade Aug 42 |
| 29 Light Anti-Aircraft Regiment – from 4 Anti-Aircraft Division Feb–Mar 42; to 65 Anti-Aircraft Brigade May 42 |
| 39 Light Anti-Aircraft Regiment – to 4 Anti-Aircraft Division by Jul 41 |
| 78 Light Anti-Aircraft Regiment – new regiment formed Jun 41; left Anti-Aircraft Command and arrived in India by Aug 42 |
| 82 Light Anti-Aircraft Regiment – from 2 Anti-Aircraft Division by May 42 |
| 121 (Leicestershire Regiment) Light Anti-Aircraft Regiment – from 62 Anti-Aircraft Brigade May 42 |
| 40 Searchlight Regiment |
| 46 Searchlight Regiment – to 3 Anti-Aircraft Division by May 42 |
| 84 Searchlight Regiment |
| 2 Anti-Aircraft Z Regiment – to 65 Anti-Aircraft Brigade May 42 |
| 62 Anti-Aircraft Brigade – to War Office Control for Operation Torch Aug 42 |
| 66 (Leeds Rifles) Heavy Anti-Aircraft Regiment – from Orkney and Shetland Defences (OSDEF) Jun 41; left Anti-Aircraft Command and arrived in India by May 42 |
| 75 Heavy Anti-Aircraft Regiment – to 6 Anti-Aircraft Division Summer 41 |
| 96 Heavy Anti-Aircraft Regiment – left Anti-Aircraft Command by May 42, later to Middle East Forces |
| 117 Heavy Anti-Aircraft Regiment – to 4 Anti-Aircraft Division by Dec 41 |
| 128 Heavy Anti-Aircraft Regiment – new regiment formed Aug, joined by Dec 41; to 31 Anti-Aircraft Brigade Aug 42 |
| 139 (Mixed) Heavy Anti-Aircraft Regiment – new regiment formed Sep 41, joined Jan 42; to 65 Anti-Aircraft Brigade Aug 42 |
| 152 (Mixed) Heavy Anti-Aircraft Regiment – new regiment formed Mar 42, to 39 Anti-Aircraft Brigade Aug 42 |
| 59 Light Anti-Aircraft Regiment – left Anti-Aircraft Command and arrived in India by Apr 42 |
| 121 (Leicestershire Regiment) Light Anti-Aircraft Regiment – converted from 44 Searchlight Regiment Jan 42; to 39 Anti-Aircraft Brigade May 42 |
| 65 Anti-Aircraft Brigade – from 5 Anti-Aircraft Division June 1942 |
| 113 Heavy Anti-Aircraft Regiment – from 39 Anti-Aircraft Brigade May 42; to mobile training Aug 42 |
| 139 Heavy Anti-Aircraft Regiment – from 62 Anti-Aircraft Brigade Aug 42 |
| 151 (Mixed) Heavy Anti-Aircraft Regiment – from 4 Anti-Aircraft Division Jul 42 |
| 29 Light Anti-Aircraft Regiment – from 39 Anti-Aircraft Brigade May 42; to War Office Control for Operation Torch Jun 42 |
| 71 Light Anti-Aircraft Regiment – from 31 Anti-Aircraft Brigade Aug 42 |
| 2 Anti-Aircraft Z Regiment – from 39 Anti-Aircraft Brigade May 42 |