Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
After the Captivity this name was applied to the whole of the country west of the Jordan (Hag. 1:1, 14, 2:2). But under the Romans, in the time of Christ, it denoted the southernmost of the three divisions of Palestine (Mt. 2:1, 5, 3:1, 4:25), although it was also sometimes used for Palestine generally (Acts 28:21).
The province of Judea, as distinguished from Galilee and Samaria, included the territories of the tribes of Judah, Benjamin, Dan, Simeon, and part of Ephraim. Under the Romans it was a part of the province of Syria, and was governed by a procurator.