[5] At the beginning of the Cold War, Canadian defence planners recognized the need for providing the Canadian Army with a suitable training facility where brigade and division-sized armoured, infantry, and artillery units could exercise in preparation for their role in defending western Europe under Canada's obligations to the North Atlantic Treaty.

The facility would need to be located relatively close to an all-season Atlantic port and have suitable railway connections.

At the same time, regional economic development planners saw an opportunity for a military base to benefit the economy of southwestern New Brunswick.

The terrain was variable, providing mixed Acadian forest, swamp and marshland, as well as open farming areas similar to the North European Plain.

[9] The base was surveyed so as to not affect some of the historic communities along the western bank of the Saint John River such as Arcadia, Hampstead, and Browns Flat; the expropriation began several kilometres west of the river and eliminated the communities of Petersville, Hibernia, New Jerusalem, North Clones[10] and others.

The training area has been heavily "landscaped" over the years by military foresters and many woodlines have been sculpted to form shapes recognizable from the air, including: Initially, Camp Gagetown was the home base for many army regiments, including The Black Watch and The Royal Canadian Regiment; however, defence cutbacks in the 1960s saw a gradual reduction, and the demise of their parent formation, 3 Brigade Group.

Principal units and formations of the CFB Gagetown are:[14][15] Portions of the training area were subject to testing of defoliants during the 1960s.

The affected areas had soil tests that measured dioxin levels at 143 times the Canadian Council of Ministers of the Environment guidelines for maximum exposure.