This is a comparative data question, so I'll research grounded estimates first, then present a table. Let me gather data on each power.

The broad searches give context. Now let me open the key sources and run more targeted searches.

The picture is clear: no single canonical dataset exists, so I'll firm up a few key figures with targeted searches before composing the comparison table.

I have enough grounded data. Now let me get the renderer details and build the visual.

Before rendering, let me verify the Roman coloniae count from the list page.

All data gathered. Now I'll render the comparison chart.

No single canonical dataset counts colonial city foundations, so the figures below are order-of-magnitude estimates anchored to documented lists where they exist. Comparison chart:

Notes on the numbers

• Spain dominates all other European powers: compilations of 16th-century foundations alone run to ~700 cities, driven by the legal privileges a municipio carried ( Ciudades fundadas por los españoles en América,  Las 700 ciudades fundadas por España en el siglo XVI), all standardized under the  Laws of the Indies.
• Rome: the 310 figure is the number of cities documented with colonia status in the  List of Roman colonies; many were veteran settlements on or beside pre-existing towns rather than new sites ( Britannica).
• Russia/USSR: Siberian colonization began with fortress-towns ( Ostrog) starting from Tyumen and Tobolsk in the 1580s ( Russian conquest of Siberia); the Soviet era added 169 documented purpose-built cities and towns ( Wikipedia category).
• Islamic expansion: the early caliphs founded a limited number of misr garrison cities, with Basra, Kufa, and Fustat the prototypes ( Amsar) — fewer than Rome or Spain, but several (Baghdad, Cairo) became million-person capitals.
• Small late empires: Germany's footprint is basically Windhoek (refounded as a garrison in 1890) ( Windhoek) and Lüderitz (1883) ( German Namibians); Italy mainly rebuilt existing ports like Asmara and Tripoli ( Italian Empire); Belgium's dozen-plus Congo stations ( Belgian Congo) urbanized a region with almost no pre-colonial cities.
• The Dutch explicitly preferred trading posts over town-planting ( Dutch colonization of the Americas), while Britain's total is a rough estimate aggregating settler towns in North America ( British colonization of the Americas), Australia, India, and Africa.

The core caveat: "founded" is defined inconsistently across these cases — de novo foundations (Spanish grid cities, Basra, Thamugadi), refoundations on indigenous sites (Mexico City, Moscow-pattern ostrogs), and status grants to existing towns (Roman coloniae). Treat the table as comparing magnitudes, not precise counts.

Fair criticism — the ~700 figure covers only the 16th century, and several other rows truncated the founding window. Let me verify the omitted centuries before correcting the table.

You're right. The ~700 figure covers only 1492–1600, and I shortchanged several other powers' windows too. I found the omissions: Spain kept founding at nearly the same pace through the 17th–18th centuries; France's Algerian settlement program alone created ~300 villages; Russia's total ignored the Black Sea steppe, Caucasus, and Central Asia. Corrected chart:

Corrected comparison:

Key corrections in detail

• Spain is the biggest fix. Even the source I cited counted only to 1599; its own 17th-century continuation shows the founding pace "prácticamente" did not drop ( Fundación de ciudades españolas… siglo XVII,  siglo XVI list, ~700), and the 18th c. is defined by mission-presidio-pueblo triads across the northern frontier ( Spanish missions in California,  Spanish missions in Texas,  Spanish colonial pueblos and villas in North America). Realistic total: ~1,000–1,500.
• Russia: my 250 covered only Siberian ostrogs. "Many cities and towns were founded on Catherine's orders," notably Yekaterinoslav, Kherson, Nikolayev, Sevastopol ( Catherine the Great); Caucasus fortress-towns like Vladikavkaz (1784) followed ( Vladikavkaz), with conquest-era foundations continuing to 1864 ( Russian conquest of the Caucasus).
• France: the villages coloniaux make the count threshold-sensitive — 42 colonies in 1848 ( Les colons de 1848, Persée) and 248 villages 1871–1895 ( Centre de colonisation, Geneawiki,  Encyclopédie de l'AFN). Count only substantial towns and France stays ~60; count every planned settlement and it rivals Britain.
• Portugal: Madeira had no prior population and was settled from 1420 — arguably the first true European settler-colony town-building, decades before the Cape route ( History of Madeira,  The Portuguese Colonization of Madeira).

The ranking order changes: Spain stays far ahead of everyone in history, but Russia's empire-total now matches the USSR, and France becomes a mid-rank founder once Algeria is counted rather than just its trading-post network. The same caveat as before applies, now more strongly: powers that planted small agricultural settlements (Spain's pueblos, France's villages, Russia's fort-towns) rank higher the more generously you define "town."