The prevalence of country names ending in "-ia" traces back to Latin, where the suffix -ia formed nouns denoting lands, regions, or territories—essentially meaning "land of" or "territory of" the root word.
The Romans used -ia extensively for provinces: Britannia (Britain), Germania (Germany), Gallia (Gaul), Hispania (Spain), Italia (Italy). This convention influenced later European naming practices.
Not all "-ia" names are Latin-derived. Romania comes from the Romanian România ("land of the Romans"), reflecting the Daco-Roman population's self-identification. Mauritania derives from the ancient Mauri people (Moors) via Latin Mauritania.
Croatia, Colombia, Bolivia, Tanzania, Zambia, Nigeria, Algeria, Tunisia, Libya, Syria, Arabia, Persia (historical), Serbia, Slovakia, Slovenia, Latvia, Lithuania, Estonia, Georgia, Armenia, Afghanistan, Pakistan (from Persian -stan but adapted), and many more.
The suffix's productivity in European languages—and through colonization, worldwide—made it a default for naming new political entities, creating a linguistic pattern that spans continents.