Judea
Historical region in southern Palestine; often used in biblical or historical contexts.
from Latin Judaea
Judea was an important region in ancient times.
Jews; Jewish people
Refers to the Jewish people collectively; often used in historical or cultural discussions.
The Jewish people have a long history.
ユダヤ denotes the Jewish ethnic/religious group, whereas イスラエル is the modern nation-state, so they are not interchangeable.
Standard katakana spelling; usually written in kana.
Rarely used kanji form (ateji).
From Latin 'Judaea', via historical and biblical transmission.