Library services for the U.S. Army Corps of Engineers (USACE) Headquarters (HQ), Humphreys Engineer Center Support Activity (HECSA), Institute for Water Resources (IWR), 249th Engineer Battalion (Prime Power) and the Army Audit Agency (AAA) are provided by librarians assigned to HECSA. The HQ/HECSA Library has two physical locations, a reading room in the GAO Building (temporarily closed) and a larger repository in Alexandria, VA, and is one of the many libraries that comprise the USACE Library Program.