51st Infantry Regiment
Modern Era, United States, Infantry
The 51st Infantry Regiment belongs to the Army's higher-numbered modern lineages, associated with the period when the United States maintained a much larger overseas and expeditionary force than in the old frontier era. Its history reflects the Army's Pacific and early twentieth-century global commitments.
Like several regiments in this range, its lineage was carried forward through reorganization, selective activation, and later battalion-era structures rather than through a continuously active field regiment. That pattern makes the 51st representative of the Army's flexible twentieth-century expansion base.
The regiment is therefore best understood as part of the wider modernization of the infantry branch, linking colonial-era and world-war needs to the later institutional Army.
Battalion Page
A dedicated battalion subpage now collects the regiment's known battalion icons and short battalion sketches for the 1st, 2d, and 3d Battalions. Open the 51st Infantry Regiment Battalions page.
Division timeline, 1916–2026 · assignments, patches and deployments →