Note: The sources and years from 1810 to 2100 come from this video:[1] When more than 20 countries reach a milestone, such as the 50 million milestone, the sources come from this video:[2] [The author can't find the sources for the population predictions/milestones, such as the UN or the USCB. These sources like YouTube are extremely unreliable sources. Whoever made those YouTube videos most likely has the UN/USCB sources.]
This is a list of population milestones by country (and year first reached). Only existing countries are included, not former countries.