The Castra of Jac was a fort made of earth in the Roman province of Dacia.

[1][2] Not far from the fort, the remains of a previous fortification (built in the 1st century BC)[2] and of a Roman watchtower[5] were unearthed.

The fort and the watchtower were abandoned in the 3rd century.

[1][5] Traces of the castra can be identified on Citera Hill in Jac (commune Creaca, Romania).

[1][2] The fort was manned by a Palmyran numerus with a detachment of horse-archers.