U.S. Army Reserve Brig. Gen. Christopher B. Creaghe assumed command of the 1st Mission Support Command at Castillo de San Cristóbal in San Juan, Puerto Rico, Dec. 12, 2025. The 1st Mission Support Command (1st MSC) in Puerto Rico has its roots in the Organized Reserves, specifically tracing lineage back to the 373rd Infantry Regiment, which was established in San Juan around 1922, evolving through various support and command structures (like the 166th Support Group) to become the modern 1st MSC, serving as the major Army Reserve command for the Caribbean and carrying forward the legacy of US Army Reserve presence in the island since that era.
