Key facts
- 4.88 million km² was the size of the Roman Empire at its biggest, in AD 117.
- 45 modern countries were part of the empire at its height.
- 43 provinces are on the map.
- Aegyptus was the largest province.
- Turkey had more land inside the empire than any other modern country.
- 58.9% of the land was in the Western half when the empire was divided in AD 395.
- 1.94 million km² was all that was left in AD 476, when the West fell.
- 977 years passed between the fall of the West and the fall of Constantinople.
- 22,624 km² was all that was left in AD 1453.
- 9,348 Roman-period towns and settlements are on the map.
Every number below is worked out by a script from the map data and is rebuilt whenever the data is updated, so nothing is typed in by hand. Each fact has its own link and a button to copy it with a citation. To see the empire at any date, open the Roman Empire map.
How big was the Roman Empire?
The Roman Empire was at its largest in AD 117, when it covered about 4.88 million km² of land (4,880,924 km²). That is the Ancient World Mapping Center outline for that year, measured on an equal-area map projection so that sizes are fair. Other estimates differ, because historians draw frontiers and count client states and seas in different ways.
The empire at its height
4.88 million km² of land lay inside the empire at its largest, in AD 117.
Published estimates vary with where the frontiers are drawn and whether client states and seas are counted.
4,880,924 km² is the exact figure for AD 117, taken from the Ancient World Mapping Center outline.
This is land only. It is a measured outline, not a count of everything Rome ever ruled.
AD 117 is the largest key date on the map. The ruler listed for it is Trajan, then Hadrian.
Between key dates the empire could have been larger. The map only measures the dates it shows.
4.81 million km² of land lay inside the empire in AD 211, the second largest date.
1.4% is how much smaller the empire was in AD 211 than in AD 117.
A change this small may be less than the uncertainty in the outlines themselves.
EPSG:6933 is the equal-area map projection used to measure every area on this site, so that places far north and far south are compared fairly.
Areas are measured before the outlines are simplified for the map.
What was inside at the peak
45 modern countries were at least partly inside the empire in AD 117.
A country counts only if enough of it lies inside the outline. Small overlaps from coastline differences are ignored.
41 of the 43 provinces on the map were held in AD 117.
43 provinces were held at once in AD 211, more than at any other key date.
Province lines come from a single map, so this counts provinces on that map rather than every historical division.
East and West
4.72 million km² of land lay inside the empire in AD 395, the year it was divided into an Eastern and a Western half.
2.78 million km² of that lay in the Western half.
1.94 million km² lay in the Eastern half, which later became known as the Byzantine Empire.
Its people kept calling themselves Romans until the end.
How did the Roman Empire grow and shrink?
Thousand km². 753 BC is left out because it is only a symbolic circle around the city of Rome. The last three dates follow modern regional borders, so their shapes are coarser.
Growing
131,515 km² was the area of the Italian peninsula that Rome controlled in 264 BC, at the start of the First Punic War.
This early date is built from modern Italian regions, so it is a rough outline.
805,540 km² was the area of the Roman Republic in 133 BC, after its first provinces overseas.
1.97 million km² was the area in 44 BC, the year Julius Caesar was killed, after the conquest of Gaul.
Dates before the Empire proper are rebuilt from the provinces Rome held, so the shapes are a guide.
3.67 million km² was the area in AD 14, when Augustus died and Tiberius became emperor.
1,692,895 km² of land was added between 44 BC and AD 14, the biggest step up in area between two key dates.
Key dates are uneven in spacing, so a long gap between dates makes a bigger step.
512.5% is how much the area grew between 264 BC and 133 BC, the biggest percentage rise between two key dates.
Percentages are biggest when the empire is small, so early steps look larger than later ones.
33.2% is how much bigger the empire was in AD 117 than in AD 14.
Slowly shrinking
1.4% is how much the area fell between AD 117 and AD 211.
The eastern gains of the earlier date were partly given up.
2.0% is how much the area fell between AD 211 and AD 395.
The fall of the West
1.94 million km² of land was left in AD 476, when the last emperor in the West was removed. Only the Eastern half remained.
58.9% is how much the area fell between AD 395 and AD 476.
This is the biggest drop in land between any two key dates.
26 modern countries that had been inside the empire in AD 395 were no longer inside by AD 476.
23 provinces that were held in AD 395 were no longer held in AD 476.
2.91 million km² of land was inside the empire in AD 565, after the reconquests of Justinian I.
49.9% is how much the area grew between AD 476 and AD 565.
All of the regained land was in the West, the part that had been lost.
The Byzantine centuries
854,602 km² was the area of the Byzantine Empire in AD 1000.
The Byzantine dates follow modern regional borders, so their outlines are coarser than the earlier dates.
591,029 km² was the area in AD 1180.
22,624 km² was all that was left in AD 1453, when Constantinople fell to the Ottomans.
This is the smallest the empire was at any date on the map apart from the city of Rome itself at its founding.
96.2% is how much the area fell between AD 1180 and AD 1453.
This is the biggest percentage drop between any two key dates.
977 years passed between the end of the Western empire in AD 476 and the fall of Constantinople in AD 1453.
Historians now call the Eastern empire the Byzantine Empire, but its people called themselves Romans.
How many provinces did the Roman Empire have?
The map has 43 Roman provinces, taken from the Ancient World Mapping Center's province map. The largest was Aegyptus, at 494,488 km², followed by Hispania Tarraconensis. Of the 43 map units, 7 combine several provinces, so the true number of provinces depends on how they are counted.
Where the source map joins provinces together, the label shows the first name only. The numbers table has the full list.
Show the numbers
| Aegyptus | 494,488 |
|---|---|
| Hispania Tarraconensis | 389,610 |
| Asia | 301,829 |
| Mauretania | 292,356 |
| Africa Proconsularis | 289,538 |
| Galatia | 263,326 |
| Aquitania | 171,508 |
| Britannia | 170,292 |
| Gallia Lugdunensis | 158,160 |
| Dalmatia and Pannonia Superior | 155,860 |
Counting provinces
43 provinces are on the map, each with its own page, capital and dates.
The source map joins some provinces into larger units, so this is a count of map units.
7 of those map units combine two or more separate provinces into one.
The page for each one says which provinces it combines.
11 provinces were Roman in more than one separate period, lost and later won back.
These are provinces retaken in the reconquests that Justinian I ordered.
Biggest and earliest
Aegyptus was the largest province, at 494,488 km².
Areas are the land inside each province outline on the map.
Hispania Tarraconensis was the second largest, at 389,610 km².
Italia (peninsula) was the earliest province to become Roman on the map, in 272 BC.
The date is the year our table of province dates gives for the land becoming Roman.
Mesopotamia was the latest to be added, in AD 198.
Which modern countries were part of the Roman Empire?
45 modern countries were at least partly inside the Roman Empire at one or more of the 13 key dates on the map. Turkey had the most land inside, at 722,597 km², followed by France and Spain. Some countries were wholly inside; others only in part.
Each country is measured at the key date when the most of it was inside.
How many countries
45 modern countries were at least partly inside the empire at one or more key dates.
A country counts only if enough land overlaps the outline, because ancient and modern coastlines do not match exactly.
39 of them have their own page, with the dates, provinces and Roman-period places inside them.
The rest are too small, or have too few Roman-period places, for a page of their own.
19 modern countries were still inside in AD 476.
2 modern countries were inside in AD 1453, at the end of the Byzantine Empire.
Land and shares
722,597 km² of Turkey lay inside the empire at most, more than any other modern country.
Measured at the key date when the most of that country was inside.
545,247 km² of France lay inside the empire at most, the second most.
495,640 km² of Spain lay inside the empire at most, the third most.
11 modern countries were entirely inside the empire at their peak.
Shares are measured against the part of each country near the Mediterranean world, so far-off overseas territories are not counted against it.
Time and places
Greece was inside the empire at 11 of the 13 key dates, more than any other country.
9,348 Roman-period towns and settlements from the Pleiades gazetteer are shown on the map.
A place counts if it is recorded as in use in a Roman period, however small.
Turkey has the most Roman-period places of any modern country, with 1,391.
Greece has the second most, with 1,176.
Roman roads facts and statistics on romanroadsmap.com →
How the Roman Empire is measured
Source and method
13 key dates are on the map, from 753 BC to AD 1453.
Between these dates the map does not show the empire.
2 key dates use the Ancient World Mapping Center outline directly.
These are the two best-sourced dates on the map.
6 key dates are rebuilt by joining the provinces Rome held at the time.
The dates are historical evidence. The shapes come from later province lines, so they are a guide.
4 key dates follow modern regional borders, because no ancient outline exists for them.
These are coarser than the others.
22 April 2024 is the date of the Ancient World Mapping Center data version used for the outlines and provinces.
The data is published under the ODbL licence.
500 km² of a modern country must lie inside the outline for it to count as inside the empire at a date.
This stops tiny overlaps caused by coastline differences from adding countries.
5,000 km² inside the empire at its biggest is enough, on area alone, for a modern country to qualify for its own page.
A country page also needs enough Roman-period places, and a large share of a small country can qualify it too.
What these numbers mean
Size depends on how you draw the edge
Nobody drew the empire as a line on a map. Frontiers were zones, and kingdoms that obeyed Rome were sometimes counted and sometimes not. That is why you will see different sizes quoted for the same year. Use the figures here as good estimates, and compare dates with each other rather than with other lists.
Some dates are sketched, others are measured
Only a few dates have a detailed outline from the Ancient World Mapping Center. The others are built from the provinces Rome held, or from modern regions, so their shapes are rougher. Large changes between dates tell you more than small ones.
A modern country is not a Roman province
Today's borders are used only to show where the empire lay. Rome never knew today's countries, and several of them sit across more than one province. The shares given for each country compare the land inside the outline with the country's land near the Mediterranean world.
Methodology
Empire outlines and provinces come from the Ancient World Mapping Center (AWMC): AWMC geodata, commit 7ecf8bc (22 April 2024). Areas are land inside the extent, measured in the equal-area projection EPSG:6933. Published estimates of the empire's size vary with how the frontiers are drawn and with whether client states and seas are counted.
A modern country counts as inside the empire at a date only if enough of it lies inside the outline, because the ancient and modern coastlines do not match exactly. Roman-period places come from the Pleiades gazetteer, and modern country outlines from Natural Earth. Changes between dates are worked out from the areas on this page.
See data sources and licences for every dataset and how it is used, and the Roman Empire by year, provinces and countries for the full lists behind these figures.
Cite this page
You are welcome to quote any number on this page. Please credit Roman Empire Map and link to this page, so readers can check the figure and see how it was worked out. Every number has its own link and a Copy citation button.
Need the numbers in a spreadsheet? Download every fact on this page as CSV.
Frequently asked questions
How big was the Roman Empire?
At its largest, in AD 117, the Roman Empire covered about 4.88 million km² of land (4,880,924 km²), measured from the Ancient World Mapping Center outline. Areas are land inside the extent, measured in the equal-area projection EPSG:6933. Published estimates of the empire's size vary with how the frontiers are drawn and with whether client states and seas are counted.
When was the Roman Empire at its largest?
The map shows AD 117 as the largest key date, in the reign of Trajan, then Hadrian. By AD 211 the empire was 1.4% smaller, at 4.81 million km².
How many modern countries were part of the Roman Empire?
45 modern countries were at least partly inside the empire at one or more of the 13 key dates, and all of them were inside in AD 117. A country counts only if enough of it overlaps the outline, so small slivers caused by coastline differences are ignored.
How many provinces did the Roman Empire have?
The map has 43 provinces, and 41 of them were held in AD 117. Of the map units, 7 join several provinces together, so a different way of counting would give a different total.
Where do these numbers come from?
Every number on this page is worked out by a script from the Ancient World Mapping Center's outlines and provinces (data version dated 22 April 2024), together with Pleiades for Roman-period places and Natural Earth for modern countries. Nothing is typed in by hand. The data sources page lists every dataset and its licence.
Can I use these facts in my article, homework or presentation?
Yes. Quote any number you like and credit Roman Empire Map with a link to this page. Each fact has a Copy citation button that copies the sentence with a link to that exact fact, and the whole list can be downloaded as a CSV file.