101 Anti-Aircraft Regiment RA (TA) was formed at Inverness in August 1939. It was re-designated as 101 Heavy Anti-Aircraft Regiment RA (TA) in June 1940. The Regiment was placed in suspended animation in December 1945. 101 Heavy Anti-Aircraft Regiment RA (TA) was reconstituted as 501 Heavy Anti-Aircraft Regiment RA (TA) in January 1947.
Illustrations of the formation badges under which a unit served or supported are given. This is no guarantee that the unit used this formations badge.
| Aug 39 |  |
3 Anti-Aircraft Division, 36 Anti-Aircraft Brigade | Inverness, UK |
| May 40 |  |
OSDEF (226 Bty Orkney) | Shetland, UK |
| Jun 41 | |
3 Anti-Aircraft Division, 51 Anti-Aircraft Brigade | North East Scotland |
| Jun 42 |  |
6 Anti-Aircraft Division, 56 Anti-Aircraft Brigade | South East England |
| Aug 42 |  |
5 Anti-Aircraft Division, 35 Anti-Aircraft Brigade | Southern England |
| Sep 42 |  |
1 Anti-Aircraft Division, 26 Anti-Aircraft Brigade | London, UK |
| Jan 43 |  |
War Office Reserve | UK |
| Jul 43 |  |
Eastern Command, 3 Indian Anti-Aircraft Brigade | Avadi, India |
| Oct 43 | 1 Royal Marine Anti-Aircraft Brigade | Bombay, India | |
| Jan 44 |  |
14 Army | India |
| Apr 44 | |
Eastern Command, 9 Anti-Aircraft Brigade | India |
| Sep 44 |  |
33 Indian Corps | Imphal, India |
| Jun 45 |  |
12 Army, 24 Anti-Aircraft Brigade | Burma (Myanmar) |
| Sep 45 | Disbanded | Rangoon, Burma (Myanmar) |
Batteries
| Aug 39 | 226, 297 |
| Jan 40 | 226, 297, 317 |
| Jun 41 | 226, 297, 379 |
| Aug41 | 226, 297, 379, 427 |
| Jul 42 | 226, 297, 379 |
| Jul 45 | 226, 297 |
Gun Sites Occupied
226 Battery
| Dates | Gun Site | Gun Defended Area |
| Aug 39-Sep 40 | H5 H6 |
Scapa |