The 113th Marine Regiment was formed on the 22nd June 2368 (Post Wolf 359) at the Marine Hostile Environment Training Facilities at the Mars 'Camp Westsmith', the regiment was originally created and activated to combat future threats on the Sol system. (Named after General Westsmith of the 20th Century USMC, who was killed by enemy action during the Eugenics' war) The 113th Marine Regiment was originally named the 14th Marine Landing Regiment (Under the Command of Colonel Denir Fasa), and the regiment's specialty was the execution of planetary assault's. Prior to the Dominion war the 14th was engaged in intensive training, and became one of the most well trained and equipped regiments of the Starfleet Marine Corp's - though it lacked any real combat experience.

With the start of the Dominion war they were immediately put on alert and transferred to Starbase 28 which was 10 days travel from the front line at maximum warp. From here the 14th Marine Landing Regiment was transferred to the 10th Fleet (Under Command of Admiral Paul Johnson) Which was protecting the planet of Betazed. The Marine Regiment was stationed at the Lalonde Starport on the Western Continent, near one of the major metropolis'. 

On stardate 51721.3 the 10th Fleet was out on a training exercise. During which a Dominion fleet from Colondra attacked. With only a token number of ships (USS Diego - Ambassador Class - Lost with all hands, USS Philip's - New Orleans class - Destroyed, 45 Crew POW status, USS F'eraki'a - Miranda Class - Heavily Damaged, Scrapped at the Alpha Centuri drydocks.) defending the planet and obsolete and undermanned planetary defenses. The initial Dominion landings took place around the Betazed capital - which fell to Dominion forces in one hour of the first landings.

Colonel Denir Fasa, ordered the 14th Marine Regiment to form a defensive perimeter, around the Lalonde Starport, and assisted with a limited evacuation of Starfleet, government and civilian personnel using the Marine transport vessels. Dominion forces struck at the Starport six hours into the battle, the Marine's held out for over four hours before the order to withdraw was given. What was left of the 14th Marine Regiment fell back to their transports and evacuated from the system, the main Dominion force consolidated their hold on the planet, leaving the transport vessels to leave the system.

Several hours later the transports arrived at Starbase 33, the 14th Marine Landing Regiment lost almost 70% of it's fighting force, Colonel Fasa died of his wounds 3 days later. 80% of the Regiment's equipment was left behind at Betazed. The unit was taken off the active list and transferred to Earth's San Francisco Marine Camp.

2375 Saw the unit reach the 85% Threshold and was made active, and was placed under the command of Lieutenant Colonel D'pui. The Regimental barracks was one of the targets of the Breen attack on Earth and Starfleet Headquarters, the Barracks were razed to the ground by Breen vessels. However the Regiment at the time was out on exercise and had been recalled to San Francisco once the Breen attack force was picked up on sensors. The 14th Marine Regiment arrived back at San Francisco once most of the main Breen strike force had been either destroyed or routed, and so was given the task to search and rescue and to maintain order in San Francisco (The city had declared a state of emergency). 

In the aftermath of the Breen attack the 14th was transferred to Camp Westsmith where it remained for the duration of the war. Once the war was over the unit was transferred to command of the 22nd Division, and renamed the 113th Marine Regiment, the unit retaining much of it's history and thus gaining the nickname of 'The lucky 13th' The 113th Marine Regiment main task since the dominion war was peacekeeping operations and the occasional border conflict.

On the date that Task Force 21 was created the Regiment was transferred to the command of Task Force 63, 4th Marine Division,  was assigned to Task Force 21 as it's Marine Contingent, and placed under the command of Lieutenant Colonel Darrel T Schreger, and it's detachments have since been engaged in the recent C'hakillian-Federation war. However the history of this unit is constantly being written by the men and women that serve in the Marine's and in Task Force 21.