This is a list of countries by population in 1900, with colonial possessions being counted towards the ruling country's total (such as Poland counting towards Russia and Cuba counting as part of the United States).
Estimate numbers are from the beginning of the year and exact population figures are for countries that held a census on various dates in the year 1900.
^The Ottoman empire was highly centralized, so certain subdivisions (such as the Cretan State) are listed separately. This total also doesn't include the tributary states of Egypt, Bulgaria, East Rumelia, Samos, or Thasos
^Martin, Frederick; Keltie, Sir John Scott; Renwick, Isaac Parker Anderson; Epstein, Mortimer; Steinberg, Sigfrid Henry; Paxton, John; (Librarian), Brian Hunter (1905). "The Statesman's Year-book".
Calendario atlante de Agostini, anno 99 [Agostini atlas calendar, year 99] (in Italian). 2003.
The Columbia gazetteer of the world. 1998.
Britannica book of the year: World Data. 1997.
Witthauer, Kurt (1958). Bevölkerung der Erde [Population of the earth] (in German).