Sejong

Annual change and the longer view

Population changed by +1,280 people (+0.3%) between 2024 and 2025.

Between 2020 and 2025, the five-year population change was +36,134 people (+10.2%). Compare this with the annual change to distinguish longer trends.

Among the years available on this page, the highest population was 391,965 people in 2025. The latest total differs from that level by 0 people. The first year is shown when a maximum is repeated.

Population and registered households

In 2025, there were 165,220 households, with an average of 2.4 people per household.

The change in registered households from the preceding year was +1,788 households.

Population and households can move in opposite directions. People per household is an average, not the share of one-person households or the most common household size. Registered households also differ from census households.

Compare with the same year nationally

This region accounted for 0.8% of Korea’s registered population in 2025.

In 2025, annual population change was -0.2% nationally and +0.3% in this region. Compare both counts and rates when regions differ in size.

Births, deaths, migration and boundary changes can affect population totals. These totals alone do not identify a cause or a policy effect. Check original table notes when administrative boundaries change.

Calculation and original data

Annual observations are year-end totals. Change is (comparison population ÷ baseline population − 1) × 100; national share is regional population ÷ national population in the same year × 100. Missing comparisons and zero denominators are not calculated. Averages and percentages are displayed to one decimal place.

• KOSIS population by administrative district and sex (DT_1B040A3)
• KOSIS registered households by administrative district (DT_1B040B3)

If a value or explanation looks wrong, send us the page URL and reference period. [email protected]