Built in 1910 and designed by John Bennes, the Armory was touted as one of the largest in the country. It currently houses the Army and Air Force ROTC programs, plus multi-use courts for basketball, volleyball and badminton, a turf field, rock climbing wall and a classroom managed by Recreational Sports. It was named for Ulysses Grant McAlexander in 1971, commandant of the cadets from 1907 to 1911 and 1915 to 1917. McAlexander was known as "Rock of the Marne" for his involvement during the eponymous 1918 battle in France. McAlexander he spent his retirement in Oregon, and is buried in Arlington National Cemetery.

In 1902, a target / shooting range was "improvised" on the land of James Hayes, just east of Scott's hill. Nearby homeowners, however, objected to its use (and to users passing through their lands to reach it), and by 1904 President Thomas Gatch was recommending "every effort be made to induce the State authorities to erect the State Target Range in this vicinity." By 1908, the range was under construction; it was completed in 1910, and measured 4,174 square feet.

The Target Range was closed permanently in June 2021.

SCARC: SCARC's holding include archival materials documenting the history of what was known as the Armory at its construction, and is now known as the McAlexander Fieldhouse.

Oregon Digital: Includes archival material documenting the history of what was known as the Armory at its construction, and is now known as the McAlexander Fieldhouse.