Renovations through 2020, included upgrades to security, seismic, environmental controls, a new envelope to support collections storage areas, the establishing of the Thomas E. Withycombe Library, and the addition of the Hall of Valor, Lobby, and Museum Store.

The surrounding Historic Park, open seasonally, features a tracked vehicle display, c1911 Battery A Field Artillery Horse Barn, and a c1911 Quartermaster Storehouse.

Within its permanent collection, OMM holds more than 15,000 artifacts including 50 vehicles, 750 small arms, 1,300 uniforms, and 1,000 demilitarized ordnances.

Since the 1970s, OMM has been amassing and preserving a collection of artifacts, archives, and images that bring Oregon's military history to life.

Smaller artifacts include trench art, homemade POW tools and equipment, dog tags, and uniforms from nearly every conflict.

The museum's archives, photo, and audiovisual collections cover over 170 years of Oregon's military history through primary and secondary source materials.