Where First Army Is Stationed and What They Do Today

Army organization has gotten complicated with all the reorganizations and mission changes flying around. As someone who’s tracked U.S. military structure for years, I learned everything there is to know about the various “First Army” formations and what they actually do. Today, I will share it all with you.

When people ask “where is First Army stationed,” they’re usually referring to the U.S. First Army – a field army with a history stretching back to World War I and a present-day mission that’s essential but often overlooked.

Location and Headquarters

Probably should have led with this section, honestly. First Army is headquartered at Rock Island Arsenal in Illinois. Rock Island sits on an island in the Mississippi River between Illinois and Iowa – a strategic location that’s served military purposes since the Civil War. The arsenal itself manufactures military equipment and houses various Army commands. First Army’s presence there gives it central positioning to manage operations across the continental United States.

The Training Mission

First Army’s current mission focuses on something less glamorous than combat operations but absolutely critical: training and mobilization of Army National Guard and Army Reserve units. These reserve component forces make up a huge portion of the Army’s total strength. When they need to deploy, First Army ensures they’re ready. That’s what makes this command so important – it’s the mechanism that transforms part-time soldiers into deployable combat power.

Organizational Structure

First Army divides its responsibilities between two subordinate commands: First Army Division East and First Army Division West. Division East handles units in the eastern United States, while Division West covers the western states. This geographic split allows tailored training support based on regional characteristics and unit concentrations. Each division oversees multiple training exercises and validation events throughout the year.

Historical Legacy

First Army was established on August 10, 1918, under General John J. Pershing’s command. It was the first American field army to fight in Europe, and its role in the Meuse-Argonne Offensive helped end World War I. During World War II, First Army landed at Normandy on D-Day and fought across Europe. The command has seen multiple reorganizations since then, but its lineage remains unbroken.

Why This Matters

The U.S. military relies heavily on reserve component forces – both National Guard and Army Reserve. These units can’t maintain combat readiness through weekend drills alone. First Army provides the intensive training that brings them up to deployment standards. When a Guard unit mobilizes for overseas operations, First Army has likely run them through validation exercises that certified their readiness. It’s not the kind of mission that makes headlines, but it’s foundational to how the Army actually operates.

First Army represents the continuity between the Army’s warfighting past and its readiness-focused present. From Rock Island Arsenal, it continues ensuring that citizen-soldiers can meet whatever challenges emerge.