The new dividing line, about 190 miles across the peninsula, sliced across Korea without regard for political boundaries, geographical features, waterways, or paths of commerce. The 38th Parallel cut through more than 75 streams and 12 rivers, intersected many high ridges at variant angles, severed 181 small cart roads, 104 country roads, 15 provincial all-weather roads, eight better-class highways, and six north-south rail lines. It was, in fact, an arbitrary separation, symbolic of the unnatural notion of two Koreas. The division of Korea along the 38th parallel was decided in America before the Korean people even knew about the capitulation of the Japanese empire.
South of the 38th parallel, the American zone covered 37.000 square miles and held some 21.000.000 people. North of the line, the USSR zone totaled 48.000 square miles and had about 9 million people. Of the 20 principal Korean cities, 12 lay within the American zone, including Seoul, the largest, with population of nearly 2 million. The American zone included six of Korea's 13 provinces in their entirety, the major part of two more, and a small part of another. The two areas, North and South Korea, complemented each other both agriculturally and industrially.
South Korea was mainly a farming area, where fully two-thirds of the inhabitants worked the land. It possessed three times as much irrigated rice land as the northern area, and furnished food for the north. North Korea furnished the fertilizer for the southern rice fields, and the largest nitrogenous fertilizer plant in the Far East was in Hungnam. Although North Korea also had a high level or agricultural production, it was deficient in some crops. The political barrier imposed serious adverse effects on the natural symbiosis of the divided zones.
In 1940, South Korea produced about 74 percent of Korea's light consumer goods and processed products. Its industry consisted of some large and many small plants producing textiles, rubber products, hardware, and ceramics. Many of these plants had been built to process raw materials from North Korea.
North Korea, a largely mountainous region contains valuable mineral deposits, especially coal. Excellent hydroelectric plants, constructed during the last 10 years of Japanese domination, ranked with the largest and best in the world. Because of its power resources, North Korea housed almost all of Korea' heavy industry, including several rolling mills and a highly developed chemical industry. In 1940, North Korea produced 86 percent of Korea's heavy manufactured goods. The only petroleum processing plant in the country, a major installation designed to serve all of Korea, was located in the north, as were seven of eight cement plants. Almost all the electrical power used by South Korea came from the north, as did iron, steel, wood pulp, and industrial chemicals needed by South Korea's light industry.