Europe:
- Roman Italy (including the Italian peninsula and nearby islands)
- Hispania (modern-day Spain and Portugal)
- Gaul (modern-day France, parts of Belgium, Switzerland, and the Netherlands)
- Britannia (modern-day Great Britain)
- Illyricum (present-day coastal regions of Croatia, Slovenia, and Albania)
- Dacia (roughly corresponding to modern-day Romania)
- Moesia (located south of the Danube river, including parts of present-day Serbia, Bulgaria, and Romania)
- Pannonia (covering parts of modern-day Hungary, Austria, Slovenia, and Croatia)
North Africa:
- Egypt
- Cyrenaica (in present-day Libya)
- Mauretania Tingitana (coastal Morocco)
Western Asia:
- Syria (including parts of modern-day Lebanon and Jordan)
- Judea and Samaria (the regions of ancient Palestine)
- Asia Minor (present-day Turkey)
The Roman Empire attained territorial expansion at various points in its history. However, some regions, such as Germania (modern-day Germany) and Persia (present-day Iran) were subject to campaigns but did not become permanent provinces of the empire.