It was part of the Separate Coastal Army, where it served for the duration of its existence. In the final defense of the Sevastopol Fortress, the 109th fought as part of the "First Sector", and its divisional commander, Maj. Gen. Pyotr Georgyevich Novikov, also served as the Sector commander. The division was tasked with the defense of the high ground that blocked German entry into Balaclava; in fact, the 456th Rifle Regiment held the same area where the British 93rd Highland Regiment made its famous "Thin Red Line" stand in October, 1854.