The 19th century lasted from 1801 to 1900.
- 1819: The United States purchases Florida and Cuba from Spain.
- 1840: The Republic of the Rio Grande declares independence from Mexico
- 1846-48: The Mexican-American War leads to the annexation of the modern Southwestern United States, down to the modern state of Durango.
- 1871: The German Empire is declared after the Franco-Prussian war is won by Prussia and her allies.
- 1871: Austria-Hungary collapses due to internal strife, leading German Austria to be annexed by the German Empire, while the remaining territory is reorganized into the Hungarian Empire.
- 1898: Spanish-American War - the United States fights against Spain, leading to the annexation of Guam, the Philippines, and Puerto Rico.