USS Sierra (AD-18) was a Dixie-class destroyer tender in the United States Navy. The ship was commissioned in 1944 and served during World War II, the Korean War, and the Vietnam War. During World War II, Sierra operated in the Pacific Theater, providing critical repair and support services to the fleet. In the Korean War, she served as a repair and replenishment ship for the United Nations fleet. In the Vietnam War, Sierra supported naval operations in the waters off Southeast Asia. Throughout her service, Sierra earned numerous awards and commendations, including the Navy Unit Commendation and the Meritorious Unit Commendation. She was decommissioned in 1992 after nearly 50 years of active service. Today, Sierra is preserved as a museum ship at Mare Island Naval Shipyard in Vallejo, California, offering visitors a glimpse into the rich history of the United States Navy.