Ulsan compared with Taipei City: area, population and density

Geography and shape

Ulsan lies on South Korea’s south-east coast, north of Busan, and is the country’s best-known heavy-industry city, with shipbuilding, car making and petrochemicals along its harbour. Its administrative territory stretches well inland over mountains and farmland. Taipei City is an inland basin with no coastline of its own.

Population context

Ulsan has 1,091,948 residents on 1,062.91 km², about 1,027 per km². Taipei City has 2,439,507 on 271.7997 km², about 8,975 per km². Taipei City has about 2.23 times Ulsan’s population on about a quarter of its land, so its average density is about 8.7 times Ulsan’s.

Boundaries and definitions

Ulsan’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. Ulsan’s area covers its whole administrative territory, including large rural and mountain districts, so the area ratio overstates its urban footprint. Its outline is drawn from Natural Earth rather than OpenStreetMap, whose relation follows a maritime boundary far out to sea; the official figure still drives the numbers — see docs/island-data-sources.md.

Ulsan: Ulsan Metropolitan City's full administrative territory, including its coastal waters for administrative purposes. 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. 🔴 The outline is drawn from Natural Earth, not OpenStreetMap: Ulsan's OSM administrative relation encloses about 2,184 km², roughly double the 1,062.91 km² official land area, because the relation follows a maritime administrative boundary far out into the sea — the same failure mode already rejected for Jeju and Bali provinces on this site. The Natural Earth admin-1 feature instead measures about 1,036 km² (about 2.5% under the official figure), which is within the tolerance already accepted for Macao and Singapore, so it draws the outline while the official figure is still used for the area and density numbers.

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.