Sejong compared with Taipei City: area, population and density

Geography and shape

Sejong sits in central South Korea, just north-west of Daejeon. It was purpose-built from 2012 to house central-government ministries relocated from the Seoul area, and holds special self-governing city status rather than being an ordinary metropolitan city. Much of its administrative territory is still farmland and hills around the new government district. Taipei City, by contrast, is a long-established capital almost entirely built up on its basin floor.

Population context

Sejong has 391,965 residents on 464.99 km², about 843 per km². Taipei City has 2,439,507 on 271.7997 km², about 8,975 per km². Taipei City has about 6.2 times Sejong’s population on about 58% of its land, so its average density is about 10.6 times Sejong’s — the widest density gap of the four Korean cities paired with Taipei City in this batch.

Boundaries and definitions

Sejong’s figures are resident registration population (주민등록인구) and official administrative area at 2025-12-31, from South Korea’s Ministry of the Interior and Safety; Taipei City uses household registration at year-end 2025. Sejong’s area is its full administrative territory, much of it rural, so the area ratio says little about the size of its new urban centre. Sejong has no coastline or islands, and its OpenStreetMap outline matches the official area within one percent.

Sejong: Sejong Special Self-Governing City's full administrative territory. Sejong is South Korea's smallest metropolitan-level city by population among the six on this page and, like Seoul, holds special-city status rather than being an ordinary metropolitan city (광역시). Population is resident registration population (주민등록인구) as at 2025-12-31, from this ministry's own annual administrative-area-and-population report — a different series from the Statistics Korea register-based census (등록센서스) that the South Korea and Seoul pages use, though the two series are usually close. Area is this same report's official administrative-area figure at 2025-12-31, not a figure computed from the map outline. This ministry's own administrative-area total for South Korea (100,517.62 km² at 2025-12-31) differs by about 0.06% from the 100,459.9 km² cadastral figure the South Korea and Seoul pages use, a small gap between two different official area series rather than an error.

Taipei City: Taipei City, the special municipality alone. Area and registered population come from the same Ministry of the Interior table at the same year-end 2025 reference date, so the density is like for like. The figure excludes New Taipei City: “Taipei” in everyday speech often means the two cities together (2,324.3664 km², 6,484,338 residents) or the wider metropolitan area, which has no single official boundary. Population is household registration, not resident presence.