The ocean to the west of the Roman Empire is the Atlantic Ocean.

Quick Scoop

When the Roman Empire was at its greatest extent under emperors like Trajan, its western lands included the Iberian Peninsula (modern Spain and Portugal) and the Atlantic coasts of places like Hispania and parts of Gaul. Those coastlines face directly onto the Atlantic Ocean, which therefore lay to the west of the empire’s territories.

The Romans themselves mostly focused on the Mediterranean, which they famously called mare nostrum (“our sea”), but their far western provinces still met the wider Atlantic world beyond the Pillars of Hercules (the Strait of Gibraltar).

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