Why Are North and South Korea Divided? Discover how the 1945 partition, the Korean War, international intervention, devastating casualties, and the 1953 armistice shaped a division that continues today.
For Koreans, the Korean War may be the most tragic war in their history. After enduring decades of Japanese colonial rule, Koreans had barely begun to celebrate their liberation when they were plunged into the suffering of a war that divided their own people.
North and South Koreans belong to the same Korean people, with a shared history stretching back to Gojoseon, the earliest Korean kingdom, as well as a common language and deep cultural roots. Yet today, North and South Korea exist as two separate countries with vastly different political systems and ways of life.
Were North and South Korea always separate countries? Why was a single nation divided in two, and why has reunification remained out of reach for more than 70 years?
To understand the answers, we need to go back to 1945, five years before the Korean War began.
1945: Why Are North and South Korea Divided in the First Place?
Korea had been under Japanese colonial rule since 1910. On August 15, 1945, Japan’s defeat in World War II brought an end to 35 years of colonial occupation.
But liberation came with an unexpected complication.
The United States and the Soviet Union agreed to divide the Korean Peninsula along the 38th parallel, a line of latitude, to accept the surrender of Japanese forces. Soviet troops would oversee the north, while American forces would take responsibility for the south.
The 38th parallel was not a border chosen by the Korean people. It was initially a military dividing line established to organize the postwar occupation.
The arrangement was not originally intended to create two permanently separate countries. However, growing tensions between the United States and the Soviet Union made Korean independence and reunification increasingly difficult.
As the Cold War intensified, the two powers failed to agree on a plan for a unified Korean government. Political divisions within Korea also deepened.
On August 15, 1948, the Republic of Korea (South Korea) was established, with Syngman Rhee as its first president.
Less than a month later, on September 9, 1948, the Democratic People’s Republic of Korea (North Korea) was established under Kim Il Sung.
For the first time, two separate governments claimed authority over the Korean Peninsula.
The situation resembled Germany’s division into East and West following World War II. However, while Germany achieved reunification in 1990, Korea remains divided today.
1950–1953: How Did the Korean War Make the Division Permanent?
After the establishment of two governments in 1948, both North and South Korea claimed that the peninsula should be unified under their respective political systems. Political tensions and armed clashes continued along the border.
Then, on June 25, 1950, North Korean forces launched a full-scale invasion across the 38th parallel, beginning what Koreans call the June 25 War (Yugio Jeonjaeng), internationally known as the Korean War.
North Korean troops captured Seoul on June 28 and rapidly advanced southward. South Korean and United Nations forces were pushed back to the Busan Perimeter in southeastern Korea. However, the successful Incheon Landing Operation in September 1950 allowed UN forces to launch a major counteroffensive.
As South Korean and UN troops advanced northward, Chinese forces entered the war, dramatically changing its course. The conflict became far more than a military confrontation between North and South Korea. It developed into a major international conflict shaped by Cold War rivalries.
To defend South Korea, 16 countries sent combat troops, including the United States, the United Kingdom, Canada, Turkey, Australia, France, and Ethiopia.
Another six countries—Sweden, Norway, India, Denmark, Italy, and Germany—are recognized by the South Korean government for providing medical assistance. Germany’s medical mission began after the 1953 armistice. Today, South Korea commemorates a total of 22 countries for their military or medical support during the Korean War and its aftermath.
The human cost of the war was devastating.
According to historical statistics compiled by South Korea’s National Archives, approximately 138,000 South Korean military personnel were killed, while around 450,000 were wounded. Including those missing or taken prisoner, total South Korean military casualties reached approximately 620,000.
UN forces also suffered enormous losses, with approximately 41,000 killed and 104,000 wounded. North Korean and Chinese forces experienced substantial casualties as well.
Civilian suffering was even more widespread. Estimates indicate approximately 990,000 civilian casualties in South Korea and 1.5 million in North Korea. These figures include people killed, injured, abducted, or reported missing, rather than deaths alone. Exact totals vary depending on the historical sources and methods used.
The destruction extended far beyond the battlefield.
According to KBS historical materials, approximately 43% of South Korea’s general industrial facilities were damaged. Cities, villages, transportation networks, and homes were destroyed, forcing millions of people to flee.
The economic consequences were equally severe. In the 1950s, per capita income was approximately $82 in India, $150 in Indonesia, $175 in Ghana, and $250 in the Philippines. After the Korean War, South Korea’s gross national income (GNI) per capita was only about $65, making it one of the poorest countries in the world.
Armistice negotiations began in July 1951, but fighting continued for another two years. Finally, on July 27, 1953, an armistice agreement was signed at Panmunjom, bringing large-scale fighting to a halt after more than three years of war.
However, an armistice is not the same as a peace treaty.
South Korea did not sign the armistice because President Syngman Rhee opposed it, favoring reunification through military force. Signed by the UN Command, North Korea, and Chinese forces, the agreement ended the fighting but left Korea divided.
The agreement also established the Korean Demilitarized Zone (DMZ), a buffer zone approximately 4 kilometers (2.5 miles) wide, centered on the Military Demarcation Line. Importantly, today’s military boundary does not follow exactly the same route as the original 38th parallel established in 1945.
Although the fighting had stopped, the war left wounds that would last for generations.
Countless children lost their parents and became war orphans. Perhaps one of the most painful consequences was the separation of families. Parents, children, brothers, and sisters found themselves trapped on opposite sides of the border, often without knowing whether their loved ones were still alive.
The tragedy was not limited to families separated between North and South Korea. Many families were also torn apart within South Korea during the chaos of the war, losing contact as they fled their homes.
Decades later, in 1983, the Korean Broadcasting System (KBS) launched a special live television program called Finding Dispersed Families (Isan Gajok-eul Chatseumnida) to help reunite family members who had lost contact with one another, particularly those separated within South Korea.
The program aired over 138 days, totaling 453 hours and 45 minutes of live broadcasting and setting a Guinness World Record. Around 100,000 people participated, and approximately 10,000 were reunited with family members they had not seen for decades. The emotional broadcasts became a powerful reminder of the Korean War’s lasting impact, and more than 20,000 related records were later inscribed on UNESCO’s Memory of the World Register.
Yet despite these remarkable reunions, many separated families, particularly those divided by the border between North and South Korea, never had the opportunity to see their loved ones again.
After 1953: Why Is Korea Still Divided Today?
As of 2026, 73 years have passed since the armistice was signed, yet no formal peace treaty has replaced it.
North and South Korea continue to exist under fundamentally different political and economic systems, and military tensions remain unresolved.
For Koreans, division is not simply a historical event. It continues to influence everyday life through military service, national defense policies, security concerns, and the experiences of separated families.
My grandfather served in the military, and his background has influenced my interest in the armed forces, national defense, and war since I was young.
Because of that personal connection, I have never thought of the Korean War as merely an event recorded in history books. Its consequences are still part of Korean society today.
Koreans have different opinions about reunification.
Some believe that North and South Korea, sharing a common history and cultural heritage, should eventually become one nation again.
Others oppose reunification because of the enormous potential economic costs and the difficulties of integrating two societies that have developed under very different systems for decades.
Personally, I hope that one day Korea can be peacefully reunified.
I understand that reunification would not be easy. The initial financial burden could be substantial, and overcoming differences in living standards, political institutions, and economic systems would take time.
Still, I believe reunification could create new opportunities in the long run.
South Korea’s advanced technology, combined with North Korea’s natural resources and the possibility of new transportation and logistics connections, could open the door to economic development.
Of course, the actual value and accessibility of North Korea’s mineral resources, as well as the economic benefits of reunification, would depend on many factors.
But I sometimes imagine Korea’s economic potential in boxing terms.
If today’s divided Korea were competing in the flyweight division, perhaps a reunified Korea could eventually move up to the heavyweight division.
That may be an optimistic dream rather than a guaranteed economic outcome, but it is a dream I do not want to give up.
I also imagine being able to travel freely throughout what is now North Korea, including Mount Paektu (Baekdusan) and Mount Kumgang (Geumgangsan), two mountains celebrated for their natural beauty.
Perhaps one day I could even board a train in South Korea, travel north across the Korean Peninsula, and continue into other countries by rail.
More than anything, I wonder what new dreams and possibilities I might discover for myself in a reunified Korea.
Closing
Korea’s division began in 1945 amid the emerging Cold War, and the Korean War in 1950 deepened that separation. The 1953 armistice silenced the guns, but it did not reunite the peninsula.
In some parts of the world, the Korean War is remembered as the Forgotten War. For Koreans, however, its consequences remain part of the present.
I hope that reunification, if it comes, will mean more than bringing two territories together. I hope it will allow people who have lived apart for generations to build a peaceful future together.