Occupying the southern 45% of the Korean Peninsula in East Asia, the Republic of Korea (ROK), also known as South Korea, has an area of 98,480 sq km (38,023 sq mi), extending 642 km (399 mi) NNE – SSW and 436 km (271 mi) ESE – WNW . Comparatively, the area occupied by South Korea is slightly larger than the state of Indiana. Bounded on the N by the Democratic People's Republic of Korea (DPRK), on the E by the Sea of Japan (known in Korea as the East Sea), on the S by the Korea Strait, and on the W by the Yellow Sea, the ROK has a total land boundary length of 238 km (148 mi) and a coastline of 2,413 km (1,508 mi). A demilitarized zone (DMZ), 4,000 m (13,100 ft) wide, covering 1,262 sq km (487 sq mi) and located north and south of the 38th parallel, separates the ROK from the DPRK, which comprises the northern part of the Korean Peninsula.
Over 3,000 islands, most of them off the southern and western coasts and belonging to the ROK, add another 8,600 km (5,350 mi) of coastline.
The ROK's capital city, Seoul, is located in the northwestern part of the country.