South Korea occupies the southern half of the Korean Peninsula in East Asia, covering about 98,500 square kilometers, roughly the size of Indiana. Despite its modest footprint, the country packs in a remarkable range of landscapes: rugged mountain chains, broad river plains, volcanic islands, and one of the most densely populated metropolitan areas on Earth.
Mountains and Terrain
About 70% of South Korea is mountainous, and two major ranges define the landscape. The Taebaek Mountains run along the eastern coast like a spine, containing over 2,048 named peaks. Their highest point within South Korea is Daecheongbong. From the Taebaek range, the Sobaek Mountains branch westward into the interior, adding another 1,572 named peaks to the country’s rugged profile.
Because the Taebaek range hugs the east coast, the terrain drops sharply toward the East Sea (Sea of Japan), creating short, steep eastern slopes and long, gentle western slopes that ease down into broad coastal plains. This asymmetry shapes nearly everything about South Korea’s geography: the biggest cities, the richest farmland, and the major rivers all sit on the western and southern sides of the peninsula.
The country’s highest point is Hallasan, a shield volcano on Jeju Island, standing at 1,950 meters (6,398 feet). It’s technically not part of either mountain range but rises from its own volcanic base in the Korea Strait, well south of the mainland.
Rivers and Drainage
South Korea’s three principal rivers, the Han, Nakdong, and Geum, all originate in the Taebaek Mountains. They wind between the mountain ranges before spreading into lowland plains near the coast. The Nakdong is the country’s second longest river at 523 kilometers, flowing southward through a drainage basin of about 23,800 square kilometers before emptying into the Korea Strait near Busan. The Han River flows westward through Seoul and into the Yellow Sea, making it the most economically significant waterway in the country. The Geum also flows west, draining the central plains.
These rivers and their tributaries created the fertile alluvial plains that historically supported rice farming and, more recently, the urban expansion of South Korea’s largest cities.
Coastline and Islands
South Korea has a long, highly irregular coastline, especially along its southern and western shores, where thousands of islands dot the water. The western coast faces the Yellow Sea and features extensive tidal flats, while the southern coast is a maze of inlets, bays, and archipelagos. The eastern coast along the East Sea is comparatively straight and steep, with fewer islands.
Jeju Island, located about 80 kilometers off the southern tip of the mainland, is the largest island by far. It’s a volcanic island dominated by Hallasan at its center, with a subtropical feel that sets it apart from the rest of the country. Ulleungdo, a smaller volcanic island in the East Sea, is notable for its dramatic cliffs and dense forest. Dokdo, a pair of tiny rocky islets about 87 kilometers east of Ulleungdo, is the country’s easternmost territory.
Climate
South Korea has four distinct seasons driven by the East Asian monsoon system. Winters are cold and dry, with Siberian air masses pushing temperatures well below freezing in the interior and northern regions. Summers are hot and humid, with heavy monsoon rains concentrated between June and September. The bulk of the country’s annual rainfall arrives during this summer window.
The southern coast, including Jeju Island, is classified as humid subtropical, with milder winters and more rainfall year-round. The rest of the country experiences a continental climate with sharper seasonal swings. In recent decades, summer precipitation has increased across most of the country, while spring and autumn have become drier.
Natural Hazards
Typhoons are the most significant recurring hazard, typically striking between July and October. These storms bring destructive winds, heavy rain, and coastal flooding, particularly along the southern coast. South Korea also has a long recorded history of earthquakes stretching back centuries, though the peninsula sits in a relatively stable tectonic zone compared to neighboring Japan. Flooding from monsoon rains remains a consistent seasonal risk, and historical records show it has been a challenge for Korean settlements for over a thousand years.
Mineral Resources
South Korea is not resource-rich by global standards, but it does have meaningful deposits of a few minerals. Limestone dominates the mining sector, accounting for about 70% of mining output by value in 2020, with major quarries concentrated in Gangwon Province in the northeast. Anthracite coal makes up another 13%, followed by smaller contributions from iron ore, quartzite, and feldspar. Gangwon Province also hosts the country’s leading iron ore mine, responsible for 96% of domestic production. Gold mining continues on a small scale in South Jeolla Province, and a tungsten mine in Yeongwol has been under reconstruction. Overall, mining and quarrying contributed about $1.2 billion to the economy in 2020, a small fraction of GDP for a highly industrialized nation.
Population and Urban Concentration
With a population density around 530 people per square kilometer, South Korea is one of the most densely populated countries in the world. That density is far from evenly distributed. The Seoul Capital Area, which includes Seoul, Incheon, and the surrounding Gyeonggi Province, holds roughly half the national population in a region that covers a small fraction of total land area. Even by the mid-1980s, Seoul alone accounted for nearly 24% of the population, and the concentration has only intensified since.
Other major population centers follow the river valleys and coastal plains: Busan anchors the southeast coast at the mouth of the Nakdong River, Daegu sits inland in the Nakdong basin, and Daejeon occupies the central Geum River corridor. The mountainous eastern interior remains the least populated part of the country. This pattern, people clustered on the western and southern lowlands with mountains largely empty to the east, is a direct reflection of the physical geography that has shaped settlement on the peninsula for millennia.