Why do the names of so many places end in -ia? [closed]

Many countries, continents, states, and cities have an English name ending in ‘-ia’:

India, Indonesia, Russia, Saudi Arabia, Australia, Asia, Alexandria, Philadelphia, California, …

What is the etymology and meaning of this suffix?

I would say it is mainly the Latin suffix -ia for names of countries as in Italia, Hispania (Spain), Graecia (Greece), Germania. -(i)a is the femine ending for adjectives. The full name of countries was "terra Italia", word for word "earth/country Italian". As terra is a feminine noun the adjectives also have the feminine ending. -ia may have a connection with ea (she).