What is an Annexation of a Country? - Definition & Examples

Instructor: Christopher Muscato

Chris has a master's degree in history and teaches at the University of Northern Colorado.

Annexation can be a very tricky political topic. In this lesson, we'll talk about what annexation is (and what it isn't) and see how people in the world generally feel about it today.


If you've ever looked at maps throughout history, you may have noticed that the borders on them tend to change. This isn't just because mapmakers of the past were less accurate, but rather because the countries themselves changed in size. How is this possible? There are a few ways to add territory to a country, and one of them is to simply incorporate another country (or parts of another country) into your own. This is known as annexation, or the transfer of political sovereignty over a chunk of land to a new state. It's just one way that nations can grow.

Examples of Annexation

Perhaps the best way to understand annexation is to briefly check out a few examples. The most common form of annexation across history has been through military conquest and control. In 1938, for example, Nazi Germany marched into Austria and conquered it. They claimed that they wanted to unify the Germanic people, and annexed the former nation of Austria into their country. From 1938 to 1945, Austria was no longer an independent country, but instead a part of Germany. It wasn't until after World War II that the annexation was reversed and the nation regained its sovereignty.

The borders of Germany expanded in WWII, thanks to annexed territories.

Examples like this can be found all throughout the past. Japan marched into Korea in the early 20th century, at which point the emperor declared parts of this colony to be formally annexed into the Empire of Japan. However, strict military conquest isn't the only path to annexation. The United States started as 13 colonies, but grew to be a nation of 50 states. How did this happen? Lots of our territorial growth came through other forms of annexation.

Texas, for example, was an independent republic that voted to allow its own annexation into the United States (aided by the fact that a large number of Americans had moved there and participated in the vote). Of course, annexation can be contested, as Mexico had yet to recognize Texan independence and claimed that Texas was still a part of Mexico. The United States, however, decided that Texas was independent, and had the right to let itself be annexed.

Later in the century, the United States annexed Hawaii, as well. In this case, American businessmen on the islands became so powerful that they overthrew the sovereign queen of Hawaii, then turned the kingdom over to the United States. In the cases of both Texas and Hawaii, the United States was able to pass resolutions in Congress that expanded the nation's sovereignty over these new lands. Military occupation wasn't a prerequisite since neither place had people in power who wanted to stop annexation from happening.

Announcement of the U.S. annexation of Hawaii.

Since the end of the World War II, the United Nations proclaimed annexation through military force to be illegal, which is why the 2014 Russian annexation of Crimea is such a big deal. The U.N. declared that this annexation used illegal military force, causing nations like the United States to impose strict sanctions upon Russia. So, annexation is still part of the modern world, although the legal authority of a nation to annex another is more strictly regulated than ever before.

Protests against the Russian annexation of Crimea.

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