Total population390,738people
Households165,930households
Average age39.5yrs
Sex ratioMale194,589peopleFemale196,149people49.8%50.2%
Population change
Change over time
4-year trendUnit: people
381,439 in 2022390,738 in 2026
Up 2.4% over the past 4 years.
Migration
As of August 2026Monthly Overview
Moved in3,610people
Moved out3,961people
Net migrationβ351people
Net migration by month
Unit: people
Net inflowNet outflow
Top origins
Unit: people
| Region | Moved in |
|---|---|
| Gyeonggi | 437 |
| Daejeon | 423 |
| Seoul | 362 |
| Chungcheongnam-do | 336 |
| Chungcheongbuk-do | 214 |
Top destinations
Unit: people
| Region | Moved out |
|---|---|
| Daejeon | 617 |
| Gyeonggi | 498 |
| Seoul | 410 |
| Chungcheongnam-do | 320 |
| Chungcheongbuk-do | 314 |
Outflows exceeded inflows in 9 of the past 12 months, for a net loss of 2,789.
Population structure
Population by age
As of September 2026Population by age and sex
Unit: people
Male 194,589Female 196,149
Age structure
Unit: %
Youth 16.4%Working age 70.6%Seniors 13.0%
40s is the largest group, at 75,683 people.
Population ranking
Population by region
As of September 2026- YoungestHapgang-dong28.5 yrs
- OldestSejong-dong61 yrs
| Region | Share | ||
|---|---|---|---|
| Jochiwon-eup | 40,949 | 10.5% | 45.6 yrs |
| Goun-dong | 35,185 | 9% | 37.3 yrs |
| Dajeong-dong | 27,811 | 7.1% | 36.3 yrs |
| Jongchon-dong | 27,224 | 7% | 38.5 yrs |
| Saerom-dong | 26,325 | 6.7% | 36 yrs |
| Dodam-dong | 24,437 | 6.3% | 39.3 yrs |
| Areum-dong | 22,959 | 5.9% | 36.7 yrs |
| Sodam-dong | 21,365 | 5.5% | 36.7 yrs |
| Boram-dong | 18,650 | 4.8% | 37.2 yrs |
| Hansol-dong | 17,581 | 4.5% | 38.9 yrs |
| Bangok-dong | 15,306 | 3.9% | 36.2 yrs |
| Sanul-dong | 14,163 | 3.6% | 31.9 yrs |
| Jiphyeon-dong | 13,197 | 3.4% | 32.3 yrs |
| Naseong-dong | 12,952 | 3.3% | 34.6 yrs |
| Eojin-dong | 11,242 | 2.9% | 34.8 yrs |
| Daepyeong-dong | 11,035 | 2.8% | 39.4 yrs |
| Haemil-dong | 9,934 | 2.5% | 34.5 yrs |
| Geumnam-myeon | 7,960 | 2% | 56 yrs |
| Janggun-myeon | 6,546 | 1.7% | 51.5 yrs |
| Yeonseo-myeon | 6,336 | 1.6% | 54.8 yrs |
| Bugang-myeon | 5,120 | 1.3% | 53.4 yrs |
| Jeonui-myeon | 4,710 | 1.2% | 56.7 yrs |
| Jeondong-myeon | 2,895 | 0.7% | 60.4 yrs |
| Yeondong-myeon | 2,609 | 0.7% | 59.2 yrs |
| Yeongi-myeon | 2,397 | 0.6% | 53.4 yrs |
| Sojeong-myeon | 1,845 | 0.5% | 56.3 yrs |
| Hapgang-dong | 2 | 0% | 28.5 yrs |
| Sejong-dong | 2 | 0% | 61 yrs |
| Nuri-dong | 1 | 0% | 49 yrs |
The top three areas hold 26.6% of the population of Sejong.
Frequently asked questionsβ
Sejong has 390,738 residents as of September 2026., 1,246 fewer than a year earlier.
Jochiwon-eup, home to 40,949 residents (10.5% of Sejong).
It is 39.5 as of September 2026., 6.2 years below the national average of 45.7. Among its neighborhoods, Hapgang-dong is youngest at 28.5 and Sejong-dong oldest at 61.
It rose 2.4% over 4 years, from 381,439 in 2022 to 390,738 in September 2026.
As of August 2026, the most people moved in from Gyeonggi (437) and the most moved out to Daejeon (617). Outflows exceeded inflows in 9 of the past 12 months, for a net loss of 2,789.
This is resident registration data from Korea's Ministry of the Interior and Safety. Figures are as of the end of September 2026 and are updated monthly. The data is open under KOGL Type 1.
Resident registration counts people at their registered address. The census counts them where they actually live. The gap is widest in university towns and industrial areas, where many people never change their registered address.
Sources π
- Resident registration data, Ministry of the Interior and SafetyKOGL Type 1 Β· as of September 2026 Β· updated monthly
- Internal Migration Statistics, Statistics Korea (KOSIS)KOGL Type 1 Β· as of August 2026 Β· updated monthly