garrisoned forces; garrison troops
Refers to military units stationed in a particular location, often overseas or in a strategic area.
There are still garrisoned forces in that country.
The withdrawal of the garrison troops was agreed upon.
駐留軍 is a broader term for 'garrison army' or 'occupation forces', while 駐留部隊 refers more specifically to the units or troops themselves.
Compound of 駐留 (ちゅうりゅう, 'stationing, garrisoning') and 部隊 (ぶたい, 'unit, force').