Exegesis:

tēs Ioudaias ‘of Judea.’ This is appropriate if Ioudaia is understood as referring to the whole territory inhabited by the Jewish people, cf. on 1.5.

Translation:

He was preaching. If an object is obligatory in the receptor language one may add a reference to what precedes, e.g. ‘he was preaching this (news),’ or a more generic term, e.g. “he continued proclaiming his message” (Phillips). For the verb see above on 3.3.

Judea, preferably, ‘the Jewish country.’

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.