South Korea occupies the southern half of the Korean Peninsula in East Asia, covering 100,363 km² with a population of about 52 million. Roughly 70% of its territory is mountainous, dominated by the Taebaek Mountains along the eastern coast, while the bulk of the population lives on the fertile western and southern coastal plains. Iconic features include Hallasan volcano on Jeju Island, the Han River basin around Seoul, the Demilitarized Zone (DMZ), and more than 3,000 offshore islands.
The geography of South Korea has shaped almost every facet of national life, from where its megacities grew to how it feeds and powers a population of more than 50 million on a land area smaller than many single US states. This guide breaks down the country's terrain, mountains, rivers, climate, coasts, resources, and human geography, and answers the questions students and travellers most often ask.
Where Is South Korea Located?
South Korea sits on the southern portion of the Korean Peninsula, which juts southward from the northeastern corner of the Asian mainland. It is bordered to the north by North Korea along the heavily fortified Demilitarized Zone, the only land boundary the country has. To the west lies the Yellow Sea (West Sea), to the east the Sea of Japan (East Sea), and to the south the Korea Strait, which separates the peninsula from Japan. This peninsular position gives South Korea an extensive coastline of roughly 2,400 kilometres, an outsized influence of the sea on its climate and economy, and a strategic location at the crossroads of China, Japan, and the wider Pacific.
Mountains and Physical Terrain
South Korea is one of the most mountainous countries in Asia, with around 70% of its land classified as hilly or mountainous. The mountains are not especially high by global standards, but they are rugged, closely spaced, and define the shape of the country. The Taebaek Mountains form the "backbone" of the peninsula, running north to south along the eastern edge and dropping steeply into the Sea of Japan, which is why the east coast is narrow and rocky while the west slopes gently toward broad plains.
Key peaks and ranges include:
- Hallasan (1,947 m): A shield volcano on Jeju Island and the highest point in South Korea, last erupting roughly 1,000 years ago.
- Jirisan (1,915 m): The highest peak on the mainland and the core of the country's first national park.
- Seoraksan (1,708 m): A dramatic granite range in the northeast famous for autumn foliage and craggy ridgelines.
- Taebaek Mountains: The dominant eastern range that channels rivers westward and creates a sharp east-west divide.
- Bukhansan (836 m): A granite massif on Seoul's northern edge and one of the world's most visited national parks per unit area.
Because the high ground is concentrated in the east, the country's rivers, farmland, and largest cities cluster in the lower-lying west and south.
Rivers and Coastal Plains
South Korea's major rivers rise in the eastern mountains and flow westward or southward to the Yellow Sea and Korea Strait, depositing sediment that built the fertile plains where most agriculture and settlement occur. The longest is the Nakdong River (506 km), which drains the southeast and reaches the sea near Busan. The Han River (494 km) flows through the heart of Seoul, and its basin alone is home to nearly half the national population. The Geum River (401 km) and the shorter Yeongsan River (130 km) water the western and southwestern rice-growing regions. The large-scale Four Rivers Restoration Project of the early 2010s reshaped and restored stretches of these major waterways for flood control, water supply, and recreation.
Islands and Coastline
South Korea has more than 3,000 islands, the vast majority scattered off the indented southwestern coast, and around 450 of them are inhabited. The largest and most famous is Jeju Island, a volcanic island south of the peninsula formed entirely by eruptions and dotted with more than 360 small parasitic cones known as oreum. The west and south coasts feature an extremely irregular, ria-style shoreline with shallow waters, enormous tidal ranges, and broad mudflats, while the east coast is comparatively smooth and steep. These tidal flats are both ecologically vital and economically important for fishing and aquaculture.
Climate and Seasons
South Korea has a temperate climate with four distinct seasons, shifting from humid continental conditions in the north to humid subtropical in the south. Winters are cold and dry, with January temperatures ranging from about -6°C to 3°C, while summers are hot and humid, averaging 23-27°C in August. The dominant climatic driver is the East Asian monsoon: the summer rainy season, known locally as jangma, delivers 60-70% of the annual rainfall of roughly 1,200-1,500 mm between June and September. Late summer and early autumn also bring the risk of typhoons sweeping up from the Pacific, which can cause flooding and wind damage, particularly along the southern coast and on Jeju.
Natural Resources and Environment
South Korea is relatively poor in mineral resources, which helped push it toward a manufacturing- and technology-based economy. Its modest mineral base includes tungsten, graphite, limestone, and anthracite coal. The seas around the peninsula are far more productive, supporting a major fishing industry centred on squid, anchovy, and seaweed aquaculture, and the broad west-coast tidal flats offer significant tidal-power potential. Today the country is best known globally as a leader in semiconductor and electronics manufacturing.
Despite dense development, South Korea retains rich ecosystems. Temperate forests cover roughly 64% of the country, Hallasan's alpine slopes form a UNESCO Biosphere Reserve, and the Suncheon Bay coastal wetlands rank among the world's top five and host thousands of wintering cranes. Perhaps the most surprising sanctuary is the DMZ itself: largely off-limits to humans for decades, the buffer zone has become an accidental refuge for more than 5,000 species, including endangered red-crowned cranes and Asiatic black bears.
Human Geography and Cities
South Korea's population of about 52 million is among the most urbanised and densely concentrated in the world. The capital, Seoul, anchors a vast metropolitan area: the city proper holds around 9.7 million people, while the wider Seoul Capital Area reaches roughly 25.5 million, more than half the national total. Other major cities include the southern port of Busan (3.4 million), the western gateway of Incheon (3.0 million), Daegu (2.4 million), and Daejeon (1.5 million). This clustering reflects the country's geography directly: people gather where the land is flat, the rivers provide water, the coasts allow trade, and transport networks tie the lowland plains together.
Key Facts
- Area: 100,363 km², roughly the size of Iceland or the US state of Indiana
- Population: About 52 million, more than half living in the Seoul Capital Area
- Highest point: Hallasan (1,947 m), a shield volcano on Jeju Island
- Longest river: Nakdong River, 506 km
- Terrain: Approximately 70% mountainous, with population on western and southern plains
- Islands: Over 3,000, of which about 450 are inhabited
- Climate: Temperate with four seasons; East Asian monsoon brings most summer rain
Frequently Asked Questions
What is the highest mountain in South Korea?
The highest point is Hallasan at 1,947 metres, a dormant shield volcano located on Jeju Island that last erupted around 1,000 years ago. On the mainland, the tallest peak is Jirisan at 1,915 metres.
How mountainous is South Korea?
About 70% of South Korea's land is mountainous or hilly, concentrated mainly in the east along the Taebaek Mountains. As a result, farming, industry, and the largest cities are squeezed onto the flatter western and southern coastal plains.
What is the longest river in South Korea?
The Nakdong River is the longest at 506 km, draining the southeast and reaching the sea near Busan. The Han River, at 494 km, is the most significant for people because it flows through Seoul and supports nearly half the national population.
Why is the DMZ important for wildlife?
Because the Demilitarized Zone between North and South Korea has been largely closed to human activity for decades, nature has reclaimed it. This narrow buffer now shelters more than 5,000 species, including endangered red-crowned cranes and Asiatic black bears, making it one of the most unexpected wildlife sanctuaries in the world.