And those of Doulichion and the Echinai, the holy islands that lie across the sea opposite Elis, -Meges the equal to Ares was their leader, the son of Phyleus. Phyleus the horseman, whom Zeus loved, was his father, but angry with his father he had gone to Doulichion. Sixty ships black followed Meges.
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Opposite Elis

Below is a more elaborate translation about Doulichion and the Echinean islands from the catalogue.

Doulichion and the holy Echinean Isles lying opposite Elis? It seems strange that Homer refers to Elis when talking about Doulichion and the Echinean Isles. Close to the Acarnanian coast would have been more appropriate. Unless, of course, Akarnania was known by another name in those days. Could the ancient name have been Doulichion? However, in other parts of the Iliad Doulichion is referred to as an island.

So, it follows that Doulichion must have been an island, or something very close to an island, and lying opposite Elis, like Acarnania does.

Opposite Elis

"I am Odysseus, the son of Laertes, known among man for my many decits, and my fame reaches to the sky. I live in clear-seen Ithaca. ... ...Round about are many other islands, close to one another -Doulichion and Same and wooded Zakynthos.

Akarnania

Elis

Echinai

Iliad Book 2 line 630-636 Barry B Powell
Odyssey Book 9 line 18-23 Barry B Powell