Introduction
The Northern Ireland District was formed in 1922, when the island of Ireland partitioned with the creation of the Irish Free State. The District comprised the six counties of the province, and had its headquarters based in Belfast. It was a Major General’s command reporting to the War Office.

The District was responsible for administering and training the Regular Army and Territorial Army units based within its area of responsibility. It was also responsible for internal security, although during this period, the conflict between the Republican Movement and the Government was at a low ebb.

Formations
There were no brigade or divisional formations stationed in Northern Ireland. In 1930, there were four British Army infantry battalions stationed in the province. In 1937, this had increased to five battalions, but at the outbreak of war in September 1939 it had returned to four battalions.