Jamaica’s records of voluntary military service date back to 1662. The Jamaica Militia, which was formed in that year, existed for nearly two and a half centuries, until it was eventually disbanded. In 1694, without any naval or regular army support, its volunteers repelled the only attempted invasion of Jamaica – by a French force of over 1,400 – other than the British, in 1655.
The name of the Reserve Unit has changed many times. In 1914, the name was changed from St. Andrew Rifle Corps (a semi-official unit formed by members of the disbanded Jamaica Infantry Militia) to Kingston Infantry Volunteers, and by 1939 to the Jamaica Infantry Volunteers. As part of the newly formed Jamaica Defence Force in 1962, the new Reserve Battalion was initially named First Battalion, The National Reserve, but in 1963 was renamed Third Battalion The Jamaica Regiment (National Reserve) (3JR (NR).
The Battalion can recall many memorable occasions in its short history. It was presented with the freedom of the City of Kingston in 1972, in recognition of its tenth anniversary. In 1975, it became the first Reserve Unit outside the United Kingdom, to parade its Colours for The Queen.
In 1980 the Government of Jamaica awarded the Certificate of Honour for Meritorious Service to 3JR (NR) for its assistance in relief operations, following the massive 1979 floods in Western Jamaica. In March 1995, the Battalion formed the Guard of Honour for the arrival of the President of Zambia on his State Visit to Jamaica. In July 1996, it was again on parade for the presentation of new Colours by the Governor-General of Jamaica.
The infantry Reserve is located in four barracks across Jamaica: Curphey Barracks – Up Park Camp; Foster Barracks – Mandeville; Burke Barracks – Montego Bay; and Whitehorne Barracks – Port Maria. Up Park Camp houses the Battalion's headquarters, the Headquarter Company, and two other companies, ‘Alpha’ and ‘Bravo’.