At its peak, the Roman Empire encompassed a land area that included present-day territories.

At its peak, commonly referred to as the Pax Romana period, the Roman Empire (27 BC to AD 476/1453) encompassed a vast territory that extended over three continents: Europe, Africa, and Asia. The empire included the whole Mediterranean coastline and stretched across Western Europe into parts of Great Britain (excluding Scotland and Ireland), south into North Africa including Egypt, and east into parts of the Middle East.

Notable present-day countries that were partly or wholly within the borders of the Roman Empire include:

- Italy (the heart of the empire) - Spain - France - Germany (mainly the southern and western regions) - England (south of Hadrian's Wall) - Portugal - Belgium - Switzerland - Austria - The Netherlands (southern parts) - Greece - Turkey (western and southern parts) - Syria - Lebanon - Israel - Northern Egyp - Libya (along the coast) - Tunisia - Algeria (eastern and coastal parts) - Morocco (northern parts)

At its height under Emperor Trajan in 117 AD, the Roman Empire was one of the most extensive political and social structures in Western civilization. Its vast territories connected a wide variety of cultures under Roman governance and a shared network of trade and communication