Seongnam's 2026 population is now estimated at 890,939. In 1980, the population of Seongnam was 376,840. Seongnam experienced a decrease of -5,107 residents over the past year, marking an annual decline of -0.57%. These population values and projections come from South Korea city census series 1980-2020 via CityPopulation official attribution and World Population Review Internal Projections .
| City | 2026 Pop. ↓ | Growth |
|---|---|---|
| Seoul | 9,217,913 | -0.65% |
| Busan | 3,233,150 | -0.59% |
| Incheon | 3,012,841 | 0.38% |
| Daegu | 2,345,915 | -0.45% |
| Daejeon | 1,430,621 | -0.66% |
| Suwon | 1,229,432 | 0.26% |
| Yongin | 1,194,265 | 1.9% |
| Hwaseong | 1,189,035 | 5.13% |
| Goyang | 1,116,116 | 1.1% |
| Ulsan | 1,099,092 | -0.54% |
| Changwon | 994,675 | -0.57% |
| Seongnam | 890,939 | -0.57% |
| Cheongju | 882,558 | 0.52% |
| Bucheon | 820,550 | -0.25% |
| Namyangju | 785,876 | 2.04% |
| Cheonan | 751,921 | 1.64% |
| Siheung | 705,258 | 4.71% |
| Ansan | 683,270 | -0.81% |
| Jeonju | 676,671 | 0.25% |
| Pyeongtaek | 665,004 | 3.45% |
| Gimpo | 640,570 | 5.13% |
| Gimhae | 575,220 | 0.68% |
| Jeju | 545,796 | 1.73% |
| Paju | 521,314 | 2.09% |
| Gwangju | 499,185 | 4.42% |
| Anyang | 495,046 | -1.51% |
| Pohang | 488,570 | -0.42% |
| Uijeongbu | 485,628 | 1.29% |
| Sejong | 477,760 | 5.13% |
| Yangsan | 428,544 | 3.37% |
| Gumi | 411,299 | -0.21% |
| Wonju | 380,184 | 1.27% |
| Hanam | 377,684 | 5.13% |
| Asan | 366,981 | 1.26% |
| Jinju | 355,567 | 0.15% |
| Gyeongsan | 290,143 | 0.37% |
| Chuncheon | 288,347 | 0.22% |
| Suncheon | 281,168 | 0.53% |
| Osan | 277,282 | 2.39% |
| Yangju | 270,860 | 2.52% |
| Yeosu | 268,822 | -0.17% |
| Iksan | 266,793 | -1.11% |
| Gunpo | 263,866 | -0.72% |
| Gunsan | 261,845 | -0.45% |
| Gyeongju | 261,141 | -0.04% |
| Gwangmyeong | 255,955 | -2.51% |
| Icheon | 248,743 | 1.59% |
| Geoje | 230,722 | -1.13% |
| Chungju | 227,644 | 0.69% |
| Gangneung | 217,585 | 0.08% |
| Seogwipo | 213,465 | 3.02% |
| Anseong | 213,412 | 0.83% |
| Mokpo | 207,728 | -1.29% |
| Guri | 207,495 | 1.3% |
| Seosan | 185,369 | 0.83% |
| Dangjin | 175,404 | 0.63% |
| Uiwang | 166,896 | 0.68% |
| Pocheon | 151,640 | -0.68% |
| Andong | 149,065 | -1.11% |
| Naju | 144,349 | 4.12% |
| Gwangyang | 143,347 | -0.07% |
| Gimcheon | 141,096 | 0.23% |
| Jecheon | 132,894 | -0.23% |
| Tongyeong | 117,730 | -1.38% |
| Yeoju | 117,590 | 0.61% |
| Nonsan | 114,479 | -0.74% |
| Sacheon | 108,657 | -0.38% |
| Yeongcheon | 103,671 | 0.54% |
| Miryang | 103,419 | 0.03% |
| Gongju | 102,397 | -0.93% |
| Jeongeup | 102,184 | -0.72% |
| Yeongju | 97,638 | -1.02% |
| Boryeong | 95,870 | -0.55% |
| Dongducheon | 92,682 | -0.45% |
| Sangju | 91,673 | -0.67% |
| Donghae | 84,944 | -0.55% |
| Sokcho | 80,304 | 0.05% |
| Namwon | 75,309 | -0.6% |
| Gimje | 74,611 | -1.1% |
| Mungyeong | 64,075 | -1.04% |
| Samcheok | 61,896 | -1.05% |
| Gwacheon | 50,794 | -2.19% |
| Gyeryong | 42,875 | 0.81% |
| Taebaek | 35,993 | -2.34% |