Naval Base Guam is a strategic U.S. naval base located on Apra Harbor, Guam. It is part of Joint Region Marianas, which is a Navy-controlled installation which was combined with Andersen Air Force Base in 2009. Naval Base Guam is home of Commander Submarine Squadron 15, Coast Guard Sector Guam and Naval Special Warfare Unit One and supports 28 other tenant commands. It is the home base of dozens of Pacific Command, United States Pacific Fleet, and Seventh Fleet units.