The Starfleet 13th Marine Regiment was a Starfleet marine regiment military unit consisting of numerous Starfleet Marines.
In the 23rd century's Four Years War between the Federation and the Klingons, the 13th was based in the Sinbad system. Along with two other regiments, the Sinbad forces scored a lucky victory over Klingon troops, counting over 30,000 Klingon ground troops killed, wounded or captured.
Three companies of the 13th were lost in the final defense of Kolm-an when a Z-4 space platform they were occupying suddenly self-destructed. (RPG reference: The Four Years War)