The Castra of Jac was a fort made of earth in the Roman province of Dacia. It was erected in the 2nd century AD. Not far from the fort, the remains of a previous fortification (built in the 1st century BC) and of a Roman watchtower were unearthed. The fort and the wathctower were abandoned in the 3rd century. Traces of the castra can be identified on Citera Hill in Jac (commune Creaca, Romania).