Karolinen, Military architectural structure in Karlstad, Sweden.

Karolinen is a multi-story complex with five to six floors made up of several interconnected buildings in Karlstad. The interior features green courtyards with water features that define the character of the entire site.

In 1971 and 1973 the Riksdag decided to relocate defence agencies out of Stockholm, and construction began in 1974 in two stages, completed in 1976 and 1978. Architect Gösta Edberg designed the building, furniture, interiors, grounds and gardens. The first occupants in 1976 were the Armed Forces Medical Board, the National Service Administration and parts of the Defence Materiel Administration and Defence Research Institute; the 1982 defence decision cut 1,500 jobs, and the Armed Forces left entirely in 2005.

The building's name refers to the karoliner, the soldiers of Charles XII, and the site long housed Swedish defence agencies. Today the entrance hall serves as a polling station on election days, and the premises host GeBlod Karlstad, where blood donors give blood, alongside offices, a restaurant and a police office.

Karolinen stands by Karl IX:s gata and Våxnäsgatan in the Klara district of Karlstad, with its main entrance used as a polling station at elections. The building holds around 1,500 rooms along roughly 16 km of corridor, so allow time to find the right section. Premises include a restaurant, offices of the Swedish Social Insurance Agency, the Police Authority and Karlstad Municipality, plus GeBlod Karlstad and Ellevio.

The building holds around 1,500 rooms and its corridors run about 16 kilometres in total. Architect Gösta Edberg designed not only the structure but also its furniture, interiors, grounds and gardens. The entrance hall doubles as a polling station during elections.