The 205th Infantry Brigade, was first formed as part of the United States Army Reserve's 103rd Division.

It was initially formed within the Organized Reserve Corps in Arizona and New Mexico, including the 409th and 410th Regiments.

In December 2006, the 205th Infantry Brigade was activated using the personnel and assets of 3rd Brigade, 85th Division (Training Support) and assumed the mission to train Army Reserve and National Guard units.

The 205th Infantry Brigade is a multi-component team consisting of active, reserve and National Guard soldiers and DA civilians with a primary focus being post-mobilization training of U.S. Army forces bound to support Operation Enduring Freedom, Operation Iraqi Freedom, and Multi National Task Force (East), Kosovo.

The brigade also has the mission of training Army Reserve units in Michigan, Ohio, and Indiana to ensure their combat readiness.