The USS Essex-B is presently under the command of Vice Admiral Deela T'Lar and is assigned to Starbase 400.
The first ship to bear the name was the Daedalus class USS Essex that entered service in Starfleet in the 22nd Century.
The next vessel named Essex was commanded by Vice Admiral T'Lar. NCC-173-A served thirteen years. During her career she would fight during the Dominion war and later the Borg invasion of 2381 as a member of the Fourth Fleet. Later as a member of the Ninth Fleet, the vessel would meet with disaster and suffer extreme damaging making repairs impossible.
In mid 2388, a new Intrepid class vessel was commissioned and named USS Essex. Command was given to Vice Admiral T'Lar. Later that year, Vice Admiral T'Lar was assigned as the new XO of Starbase 400. Her flagship, USS Essex, and its Senior Staff joined Starbase 400 with her. During that year, the Essex made patrols along the Federation border of the Triangle. Later that year, a Task Force comprising the Starships Pegasus-B, Yorktown-E, Essex-B, Defiant, Saratoga, Avenger-A, and Sutherland left Starbase 400 to investigate the possibility of a Dominion base on Iconia, left over from the Dominion War. Once in the system, Odo contacted the planet and the Vorta Deyos explained he was ordered to hold the planet by the Female Founder and refused to surrender. A Jem'Hadar fleet of six Attackships and one Battleship attacked the Starfleet task force and the USS Yorktown-E was destroyed. However all of the Dominion Attackships were destroyed and the Battleship was neutralized. A joint Marine/Security/Jem'Hadar Commando assault force beamed down and managed to secure the Outpost. Deyos was captured, and later orderd the Jem'Hadar garrison to stand down after speaking to the Female Founder via subspace. However the assault force suffered heavy casualties, including Major Hurd and Admiral Bremer, both being severely wounded.
In early 2389, While on their way for a family vacation, a runabout carrying Admiral Bremer's family was attacked. Marc and Emmaline Bremer were killed, Janice Bremer and Christopher Bremer were severely injured, and K'Wor was kidnapped. Admiral Bremer, who had to stay on Starbase 400 for a high level meeting, took the Pegasus-B to the site of the attack where the crew began recovering the casualties and investigating who attacked the runabout and why. Becca Bremer was unharmed, she had remained on Starbase 400 with her father. During the investigation, the crew of the Pegasus-B discover three tricobalt charges have been planted against the ship's hull. Captain Pike and Lieutenant Vid-Lotilija manage to deactivate two before the third detonated, injuring both and damaging the ship. It was discovered that Jon Westmoreland, former USS Pegasus-A Chief Security/Tactical Officer was behind the attack on Bremer's Family. The Pegasus-B gave chase. Meanwhile, Vice Admiral T'Lar found evidence that Admiral Riggs at Starfleet Command was aiding Westmoreland, and she took the Essex to Earth to investigate. The Essex arrived at Earth to question members of Starfleet Command while attempting to track down and detain Admiral Riggs. The Starlighter, Westmoreland's private craft, arrived at Remu III and landed at a previously unknown smuggler base. The Pegasus-B arrived a few minutes later and beamed down Marines. Admiral Bremer led the rescue team to find his son. The rescue team from the Pegasus-B recoverd K'Wor and Bremer kills Westmoreland in personal combat. The crew of the Essex apprehends Admiral Riggs. Riggs admits to aiding Westmoreland. It's discovered that Riggs falsified records during the Dominion War, and Westmoreland was using that information to force Riggs to help him. They also learn Westmoreland's hate for Bremer goes back thirteen years to the Pegasus-A's mission to stop the USS Universal's attack on the Cardassian planet Remu III following the Dominion War. Westmoreland's wife had been killed aboard the USS Universal and he blamed Bremer for her death. The Pegasus and Essex later returns to Starbase 400.
Currently, the Essex is assigned to station Starbase 400, where Admiral T'Lar serves as station Executive Officer.