Mark H. Landes is a career officer in the United States Army. A 1990 graduate of the United States Military Academy, and a veteran of the Iraq War, War in Afghanistan, and Operation Inherent Resolve, he was promoted to major general in 2021. Landes' commands included 2nd Battalion, 23rd Infantry Regiment, 3rd Brigade, 1st Armored Division, Security Force Assistance Command, and First Army Division East.

First Army Division East is a division of the First United States Army. With its new role, the First Army developed two subordinate multi-component headquarters – one division to support the eastern United States and the other to support the western United States. First Army Division West was activated at Fort Carson, Colorado, and later moved to Fort Hood, Texas. First Army Division East was activated on 7 March 2007 at Fort George G. Meade, Maryland, and later moved to Fort Knox, Kentucky.