A border is a real or artificial line that separates geographic areas. Borders are political boundaries.


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Geography, Human Geography, Physical Geography, Social Studies, World History

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A border is a real or artificial line that separates geographic areas. Borders are political boundaries. They separate countries, states, provinces, counties, cities, and towns. A border outlines the area that a particular governing body controls. The government of a region can only create and enforce laws within its borders.

Borders change over time. Sometimes the people in one region take over another area through violence. Other times, land is traded or sold peacefully. Many times, land is parceled out after a war through international agreements.

Sometimes, borders fall along natural boundaries like rivers or mountain ranges. For example, the boundary between France and Spain follows the crest of the Pyrenees mountains. For part of its length, the boundary between the United States and Mexico follows a river called the Rio Grande. The borders of four countries divide Africa’s Lake Chad: Niger, Chad, Cameroon, and Nigeria.

Borders—particularly national borders—affect travel and migration. People can usually move freely within their own country’s borders, but may not be allowed to cross into a neighboring country.

When neighboring countries have similar wealth and political systems, their borders may be open and undefended. For example, citizens of the 27-country European Union may travel freely among any of the member states. Only five EU members—Bulgaria, Cyprus, Ireland, Romania, and the United Kingdom—require travelers from other EU states to present a passport or ID card at the border.

On the opposite extreme, the Korean Demilitarized Zone—the border between communist North Korea and democratic South Korea—is the most heavily militarized border in the world. The zone, which is 4 kilometers (2.5 miles) wide and 243 kilometers (151 miles) long, separates the two countries with barbed-wire fences, land mines, and armed guards. Citizens of most countries must have a passport and official permission to enter the borders of North Korea. North Koreans must also have official permission before they leave the secretive nation.

Every country has its own rules about who may travel, work, and reside within its borders. Visas and work permits are government documents issued to non-citizens that limit the type of work or travel they may do in the country, and for how long. The United States issues “green cards”—officially known as permanent resident cards—that allow non-Americans to live and work inside the borders of the U.S. and be protected by its laws.

Border Protection

Most countries have some sort of military or law-enforcement presence along their borders. Countries protect their borders for several reasons. One is to keep out invaders. This is especially true in areas where two or more countries have fought over the same land for many years. Cambodia and Thailand, for example, have disputed the territory of the Preah Vihear Temple for more than a century. Cambodian and Thai military units are positioned along the border near Preah Vihear Temple, and skirmishes often result in deaths on both sides.

Sometimes, borders serve to keep citizens in. Most governments with these “closed borders” are not democratic. In addition to North Korea, nations such as Myanmar and Cuba rarely allow their residents to cross their borders.

Borders can also serve to protect resources. Sometimes, the borders of U.S. congressional districts protect ethnic, religious, or economic communities. Citizens within these borders often vote as a unit, based on shared political beliefs. The area’s representative in the U.S. House of Representatives must be aware of the interests within his or her district’s borders. The concerns of a representative from the urban area of St. Louis, Missouri, for instance, are less likely to be issues affecting farmers than a representative from rural Missouri, which is dominated by agriculture. The representative from rural Missouri would be less likely to be concerned with issues surrounding public transportation, which is much more common in cities.

Border Disputes

Many border disputes occur when people fight over natural resources. For instance, Sudan and Egypt have quarreled for decades over a region called Hala’ib. This triangle of land along the Red Sea is rich in the mineral manganese, which is essential to iron and steel production. It is also used as an additive in unleaded gasoline. The Sudanese government claims the land rightfully belongs to Sudan, but it currently belongs to Egypt.

Many times, political borders divide groups of people who share a common religion, culture, ancestry, or language. The border between North Korea and South Korea, for example, is a purely political one; the Korean people share a united history, culture, and language. The nation of Germany was divided between East Germany and West Germany from 1949-1989. Like the Korean border, this was a purely political division, between the democratic West and the communist East. Germany reunified in 1990, and the border disappeared.

Many times, one ethnic group wishes to break off and form its own, independent state. This can lead to civil war.

The area of southeastern Europe on the Balkan Peninsula (known as the Balkans) has a long history of ethnic conflict and disputed borders. The country of Yugoslavia was created from many small political units after World War I. After World War II, Yugoslavia became a communist country under Marshal Josip Broz Tito. Despite Yugoslavia’s many different languages, cultures, and religions, Tito and his successors were able to maintain a stable nation until the fall of communism in the early 1990s.

After the fall of communism, however, democratic movements swept central and eastern Europe. Autocratic rulers were unable to maintain power. In the Balkans, ancient feuds began to resurface. Bosnians, Serbs, Croats, Macedonians, and Slovenians began vying for control of the region. Even within these national groups, ethnic or religious minorities pursued independence: Bosnian Serbs sought independence from Bosnia, while citizens of the Kosovo region sought independence based on their Muslim identity. The area that used to be Yugoslavia now consists of seven countries: Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Macedonia, Montenegro, and Kosovo. The crimes surrounding the border disputes between these countries are so numerous and graphic that an entire court in the International Criminal Court is devoted to them: the International Criminal Tribunal for the Former Yugoslavia (ICTY).

Border issues often arise when outside powers draw borders in regions they colonize, with or without the consent of the people who already live there. During the 1800s and 1900s, European countries colonized much of Africa. These European colonists created the borders of most African countries. The divisions often did not reflect the existing ethnic or political groups that lived in those regions. The so-called “Scramble for Africa” was a conflict between European powers on African soil. European nations, led by the United Kingdom, France, and Belgium, competed to amass the most land and resources in Africa, with little regard for natural boundaries or cultural borders.

By the late 1960s, most African nations had gained independence. As colonial powers withdrew from the continent, they often left a power vacuum that allowed old tribal conflicts to resurface. For example, after Belgian troops withdrew from Central Africa, two tribes—the Hutus and Tutsis—began fighting. In 1962, two new countries were formed. Rwanda was led by Hutus, while Burundi was led by Tutsis. Fighting continued until it came to a head in 1994 with a devastating civil war in Rwanda that left hundreds of thousands of Tutsis and moderate Hutus dead. The Tutsis took control, forcing millions of Hutus to flee into nearby Democratic Republic of Congo (then called Zaire) and Tanzania.

African leaders are working to establish stable, peaceful borders. In January 2011, the citizens of southern Sudan voted to secede from Sudan and form their own nation. The president of Sudan accepted the vote. The border between Sudan and the proposed nation of Southern Sudan has not been disputed. The regions are ethnically and religiously distinct, with Arab Muslims dominating the culture of Sudan and Christian Africans dominating the culture of Southern Sudan.

Border disputes can also develop as communities seek to establish their own city. This process is called incorporation. Many rural or suburban residents resist incorporation. They prefer to be an unincorporated part of a county, instead of affiliated with a town or city. They say it will lead to more taxes and government rules.

Other residents support incorporation and setting their own borders. They say incorporating as a town or city will allow them more independence on issues of law enforcement, education, and land use.

Fast Fact

Friendly Neighbors
Canada and the United States share the world's longest undefended border, stretching 6,416 kilometers (3,987 miles).

Fast Fact

Kurds Way
The Kurds are the largest ethnic group in the world without their own state. There are approximately 35 million Kurds living throughout Turkey, Iran, Iraq, Syria, and Armenia. They often face hostility and violence in the countries where they live. For example, Iraqi soldiers destroyed more than 4,000 Kurdish villages and killed as many as 182,000 Kurds in the 1980s. The Kurds have longed for their own state in Kurdistan for centuries, but so far have been unable to accomplish this goal. Nations are rarely willing to relinquish their borders.

Fast Fact

Meandering River
The border between Mexico and the U.S. state of Texas follows the Rio Grande. During the mid-1800s, the river shifted its course southward, giving the U.S. an extra 600 acres of land. For many years, the two countries fought over this territory. The dispute wasn't officially settled until 1963.

Media Credits

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Diane Boudreau
Melissa McDaniel
Erin Sprout
Andrew Turgeon
Mary Crooks, National Geographic Society
Tim Gunther, Illustrator
Jeannie Evers, Emdash Editing, Emdash Editing
Kara West
Educator Reviewer
Nancy Wynne
National Geographic Society
Last Updated

November 28, 2023

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