Hydai or Kydai was a town of ancient Caria. Its name does not appear in ancient authors, but is inferred from epigraphic evidence; its demonym was Hydaieis (Ancient Greek: Ὑδαιεῖς) or Kydaieis (Κυδαιεῖς). It was a polis (city-state) and a member of the Delian League.
- Mogens Herman Hansen & Thomas Heine Nielsen (2004). "Karia". An inventory of archaic and classical poleis. New York: Oxford University Press. pp. 1116–1117. ISBN 0-19-814099-1.
- Richard Talbert, ed. (2000). Barrington Atlas of the Greek and Roman World. Princeton University Press. p. 61, and directory notes accompanying.
- Lund University. Digital Atlas of the Roman Empire.