Hertsön is a Swedish island in the Bothnian Bay, largely occupied by the eastern districts of the city of Luleå.
  Hertsön | |
| Geography | |
|---|---|
| Coordinates | 65°35′03″N 22°11′58″E / 65.584159°N 22.199539°E |
| Adjacent to | Bothnian Bay |
| Area | 73.42 km2 (28.35 sq mi)[1] |
| Administration | |
| County | Norrbotten |
| Municipality | Luleå |
Due to post-glacial rebound, the islands Svartön, Mulön, Granön and Björkön have merged with the island. The size of the island is around 73.42 km², making it the twelfth largest island in Sweden.