Seongnam's 2025 population is now estimated at 943,458. In 1950, the population of Seongnam was 54,507. Seongnam has grown by 1,299 in the last year, which represents a 0.14% annual change. These population estimates and projections come from the latest revision of the UN World Urbanization Prospects . These estimates represent the Urban agglomeration of Seongnam, which typically includes Seongnam's population in addition to adjacent suburban areas.
| City | 2025 Pop. ↓ | Growth |
|---|---|---|
| Seoul | 10,025,800 | |
| Busan | 3,484,430 | |
| Incheon | 2,873,700 | |
| Daegu | 2,181,080 | |
| Gwangju | 1,536,730 | |
| Gwangju | 1,536,730 | |
| Daejeon | 1,365,961 | |
| Goyang-si | 1,073,069 | |
| Changwon | 1,056,980 | |
| Seongnam-si | 1,031,935 | |
| Suwon | 944,239 | |
| Ulsan | 916,236 | |
| Bucheon-si | 850,731 | |
| Cheonan | 713,308 | |
| Jeonju | 667,908 | |
| Ansan-si | 650,728 | |
| Cheongju-si | 634,596 | |
| Anyang-si | 634,367 | |
| Uijeongbu-si | 479,141 | |
| Hwaseong-si | 476,297 | |
| Masan | 434,371 | |
| Jeju City | 408,364 | |
| Gumi | 401,111 | |
| Pohang | 367,474 | |
| Kwangmyong | 357,545 | |
| Kimhae | 356,242 | |
| Namyangju | 339,545 | |
| Iksan | 322,636 | |
| Chinju | 307,242 | |
| Yeosu | 303,115 | |
| Gyeongju | 275,132 | |
| Gunsan | 272,129 | |
| Wonju | 267,849 | |
| Suncheon | 265,724 | |
| Chuncheon | 252,177 | |
| Mokpo | 250,336 | |
| Gangneung | 227,856 | |
| Icheon-si | 196,230 | |
| Guri-si | 195,236 | |
| Yangsan | 191,147 | |
| Andong | 181,974 | |
| Asan | 179,900 | |
| Gimcheon | 147,269 | |
| Seogwipo | 145,732 | |
| Seosan | 142,972 | |
| Nonsan | 137,452 | |
| Anseong | 132,906 | |
| Gongju | 130,223 | |
| Gyeongsan-si | 129,903 | |
| Jeongeup | 128,892 | |
| Hanam | 120,149 | |
| Sangju | 116,365 | |
| Miryang | 115,787 | |
| Yangju | 107,440 | |
| Hwado | 106,358 | |
| Osan | 102,287 | |
| Tonghae | 101,128 | |
| Naju | 99,233 | |
| Yeoju | 97,412 | |
| Wabu | 96,775 | |
| Mungyeong | 90,778 | |
| Kwangyang | 89,281 | |
| Hongseong | 89,174 | |
| Sokcho | 87,880 | |
| Eisen | 84,625 | |
| Wanju | 84,009 | |
| Yangp'yong | 83,367 | |
| Ungsang | 83,360 | |
| Sinhyeon | 82,560 | |
| Naeso | 80,987 | |
| Sejong | 79,745 | |
| Muan | 75,718 | |
| Hongch'on | 75,251 | |
| Changnyeong | 74,668 | |
| Koch'ang | 72,996 | |
| Kyosai | 72,124 | |
| Hwawon | 64,718 | |
| Pubal | 63,026 | |
| Kosong | 62,446 | |
| Taisen-ri | 62,039 | |
| Chinch'on | 60,964 | |
| Hwasun | 59,914 | |
| Nangen | 58,057 | |
| Okcheon | 56,634 | |
| Eisen | 56,006 | |
| Gapyeong | 55,415 | |
| Yeongam | 55,000 | |
| Sinan | 53,150 | |
| T'aebaek | 48,962 | |
| Kimje | 44,894 | |
| Koesan | 44,461 | |
| Munsan | 43,208 | |
| Gijang | 43,064 | |
| Santyoku | 42,145 | |
| Yeonil | 40,852 | |
| Hayang | 40,423 | |
| Yesan | 39,409 | |
| Imsil | 37,514 | |
| Heunghae | 36,080 | |
| Kunwi | 34,293 | |
| Tangjin | 32,778 | |
| Fuyo | 32,642 | |
| Cheongsong gun | 31,313 | |
| Jinan-gun | 31,273 | |
| Kurye | 30,000 | |
| Waegwan | 29,691 | |
| Seonghwan | 29,239 | |
| Goseong | 26,704 | |
| Changsu | 26,463 | |
| Ganghwa-gun | 25,535 | |
| Neietsu | 25,413 | |
| Kinzan | 25,243 | |
| Yonmu | 25,015 | |
| Yong-dong | 24,154 | |
| Yanggu | 24,027 | |
| Haenam | 23,928 | |
| Hwacheon | 23,822 | |
| Gaigeturi | 23,717 | |
| Taesal-li | 23,149 | |
| Puan | 22,267 | |
| Jenzan | 20,673 | |
| Yeonggwang | 19,909 | |
| Beolgyo | 19,842 | |
| Sintansin | 15,000 | |
| Yongsan-dong | 12,612 |