Carsium was a fort in the Roman province of Moesia in the 1st century AD^[3][4] whose remains are still visible. It was part of the defensive frontier system of the Limes Moesiae along the Danube.

Carsium
Fort tower
Location within Romania
Alternative name(s)	Carsion,[1] Carsum,[2] Carsio,[2] Carso,[2] Carsos [2]
Known also as	Fortress of Hârșova, Castra of Hârșova
Founded	1st century AD[3][4]
Abandoned	3rd[3] or 6th century AD[4]
Attested by	Tabula Peutingeriana, Itinerarium Antonini, Notitia Dignitatum
Previous fortification	Dacian
Place in the Roman world
Province	Moesia
Administrative unit	Moesia Inferior
Directly connected to	Capidava, Ulmetum, (Izvoarele)
Structure
— Stone structure —
Built during the reign of	Trajan[2]
Built	103 [2]
— Wood and earth structure —
Stationed military units
— Legions —
vexill. I Italica,[2] vexill. I Iovia (Scythica)[2]
— Alae —
II Hispanorum,[2] I Gallorum Flaviana[2]
— Classis —
Flavia Moesica[2]
Location
Coordinates	44°40′53″N 27°57′08″E / 44.6814°N 27.9523°E / 44.6814; 27.9523
Altitude	c. 24 m
Town	Hârșova
Country	Romania
Reference
RO-LMI	CT-I-s-A-02676[4]
RO-RAN	60810.01[3]
Site notes
Recognition	National Historical Monument
Condition	Ruined

A Roman settlement grew up on the site of the current town of Hârșova around the Roman fort. It was initially in Moesia and later in Scythia Minor province.