South Korea has an abundance of mountain ranges running in all directions. Approximately 70% of the total land surface is mountainous. Only about 15% of the land can be considered lowland, and this is mostly the product of erosion. Consequently, there are few areas devoid of hills that could be considered "plains" in the common usage of the word. Inchon is located on the Kimpo Plain in the Han River Lowlands. Pyongtaek is approximately 30 nmi south-southeast of Inchon on the Pyongtaek Coastal Plain and has similar topographical characteristics.

The highest elevations of the rugged topography of South Korea are mostly aligned north-south along the eastern one-half of the country. Elevations in the hills and mountains east of Pyongtaek generally range from 2,000 to 5,000 ft (610 to 1,524 m), with the highest peak on the peninsula, Chirisan, reaching 6,283 ft (1,915 m). The highest elevations within 60 nmi north and west of Pusan are in the 500 to 3,000 ft range.

The country in the vicinity of Pusan is almost devoid of trees, except for Yongdo and the city itself. The hills, which in general parallel the coast, are covered to their summits by a rank growth of grass. In autumn and winter this grass takes on a brownish, barren appearance with outcroppings of rock. Cultivated areas lie in the valleys, between the spurs running down to the shore.

As can be seen in Figure 16, Pusan is afforded limited protection by elevations exceeding 1,000 ft north, west and south of the Harbor, but is open and exposed to east-northeasterly, southeasterly and southwesterly winds.

One of the principal peaks near the coast in the Pusan area is Kudok San (35°07'N 129°00'E), about 2.8 nmi northwest of Yongdo. Kumyor (Gumyeon San) has two summits. The highest reaches an elevation of 1,404 ft (428 m) about 5 nmi northeast of Kudok San. Chan San (Jang San), lying about 4 nmi farther northeast of Kumyor (Gumyeon San), has an elevation of 2,080 ft (634 m).

Yongdo, which separates the North Harbor form the South Harbor, rises to Bongrae San (Pongrae San) at an elevation of 1,296 ft (395 m). It is located on the northern part of the island. The hills slope down to its north and northeast shores. The southwest coast consists of steep cliffs. The reclaimed land on the northeast side of Yongdo is fronted by the coastal bank, which at the north end is encumbered with rocks. Several radio masts and towers stand on the island.

More detailed information on South Korean topography can be found in the South Korea Forecaster's Handbook in the Publications Section of the Naval Research Laboratory web site at