Aigeira, also Aegae, or Aigai (, Modern Greek: Αιγές) was an ancient settlement in Achaea located northwest of modern Aigeira. It was situated near the river Krathis, between the towns Boura and Aigeira. There was a cult of Poseidon in the town, and it was abandoned in or before the 3rd century BC.
The location of the ancient city has been found and excavated near Aigeira.
Aegae ( Aigai) was an ancient town on the west coast of the island of Euboea, opposite the mainland city of Anthedon. The geographer Strabo records a sanctuary of Aegean Poseidon on a mountain nearby.
It seems to be dinstict of legendary Aegae, the namesake of the Aegean Sea, which was situated on the east coast of the island, near modern Kymi. It's not unlikely that Aegae got actually switched to Kymi/Cuma, as the generic name Kymi/Cuma, just means city in the Aeolic dialect.
Legendary Aegae is mentioned e.g. by Homer in Book 5 of the Odyssey, in which Poseidon "lashed his long-maned horses and drove to Aegae, where he had his famous palace" after having destroyed Odysseus' raft with a storm. It was also mentioned by Homer in Book 13 of the Iliad, in which Poseidon "[took three strides], and with the fourth he reached his goal—Aegae, where is his glittering golden palace, imperishable, in the depths of the sea."