An internment camp was a type of prison where groups of people considered enemies of the state were confined.
During their conflict with the Suliban Cabal in the 2150s, the Tandarans established internment camps to house their resident Suliban population regardless of whether they were aligned with the Cabal. One such camp was Detention Complex 26. Based on Earth's historical experience, Captain Jonathan Archer decided to liberate the camp in 2152. (ENT: "Detained")
The Dominion operated internment camps such as Internment Camp 371, where a number of individuals from the Alpha Quadrant were held in 2373. (DS9: "In Purgatory's Shadow") Ishka was briefly held at an internment center after her capture by the Dominion in 2374. (DS9: "The Magnificent Ferengi")