The 162nd Infantry Regiment traces its lineage back to 20 May 1887, when the Infantry Brigade of the Oregon National Guard was organized from existing state militia companies. The brigade included the 1st, 2nd, and 3rd Infantry Regiments. Companies G and K of the 2nd Regiment were detached and reorganized as the Separate Battalion, Infantry in 1893, but the battalion was discontinued in 1896 and the two companies became separate units within the brigade. The 3rd Regiment was reduced to the 3rd Battalion, Infantry in March 1896. During the Spanish–American War, the Infantry Brigade was mustered into Federal service as the 2nd Oregon Volunteer Infantry Regiment at Portland between 7 and 15 May 1898. After service in the Philippine–American War, the regiment mustered out at San Francisco on 7 August 1899. The Portland elements of the brigade were reorganized as the 3rd Regiment of Infantry on 3 May 1900.
