‘There is an isle, Ogygia, which lies far off in the sea. Therein dwells the fair-tressed daughter of Atlas, guileful Calypso, a dread goddess, and with her no one either of gods or mortals hath aught to do; but me in my wretchedness did fate bring to her hearth alone, for Zeus had smitten my swift ship with his bright thunderbolt, and had shattered it in the midst of the wine-dark sea.’   Odyssey 7.244ff. (online text: Eng., Grk.)
[here and below quotes are selective; follow links for complete passages]

Ancient Localization

Apollonius of Rhodes, Argonautica 4.573-575

“And next they passed Melite, rejoicing in the soft-blowing breeze, and steep Cerossus, and Nymphaea [an island in the Adriatic] at a distance, where lady Calypso, daughter of Atlas, dwelt.”   (online text: Eng., Grk.)

Strabo, Geography 7.3.6

“… Callimachus cannot be pardoned at all, because he makes a pretence of being a scholar; for he calls Gaudos the “Isle of Calypso” and Corcyra “Scheria.”
(online text: Eng., Grk.)

Pomponius Mela, Description of the World 2.120

“Near Sicily, in the Sicilian Strait, is the island of Aeaee, which Calypso reportedly inhabited.”  [wrong goddess, vague and idiosyncratic locale for Circe] (online text: Eng., Lat.)

Pliny the Elder, Natural History 3.10

“…there are besides, Mount Clibanus, the promontory of Lacinium [Capo della Colonne, near Crotone], in front of which lies the island of Dioscoron, ten miles from the main-land, and another called the Isle of Calypso, which Homer is supposed to refer to under the name of Ogygia.” [so also Ps. Scylax 13; there is no such island] (online text: Eng.Lat.)

Plutarch, On the Face in the Moon 26

“…beginning, if there is nothing to hinder, with that of Homer, ‘an isle Ogygia lies in Ocean’s arms’ [Od. 7.244], distant about five days’ sail westward from Britain … ”
(online text: Eng., Grk.)