Fort I Barracks with the Osowiec Fortress Museum

The Osowiec Fortress Museum opened in 1998 through the work of the Osowiec Fortification Society. Its collection was placed in the historic garrison setting rather than a new museum building. The former barracks belonged to Fort I's support infrastructure. Alongside soldiers' accommodation, the citadel contained a hospital, stores and officers' houses. This layout distinguished living and organisational functions from positions used directly in combat.

Museum presentations used weapons, uniforms and photographs. Equipment and armaments added the experience of military service to an account otherwise told through walls and ramparts.

A historical and nature trail opened alongside the museum. This marked a stage in making part of the military heritage accessible for learning about its history. It did not establish a permanent right of access to the garrison: Fort I, where the museum was established, is currently closed to visitors.