|Area||147.54 km2 (56.97 sq mi)|
The area of the island is 147 km2, and the area of the municipality is 168 km2. The population, as of 2017, was 15,774 people.
Tjörn is connected in the east to the town of Stenungsund on the mainland by the Tjörn Bridge, and to the island of Orust in the north by the Skåpesund bridge. The largest town is Skärhamn, and it is also the municipal capital. Other communities, many of which are fishing communities, include Rönnäng, Klädesholmen, and Kyrkesund. The peninsula of Mjörn has large shell banks.
During the summer, the population swells from 15,000 to 45,000 as vacationers arrive for yachting and swimming. Skärhamn has a guest harbor to accommodate yachters travelling along the Swedish west coast.
- "Statistisk årsbok 2011" (PDF) (in Swedish). Statistics Sweden. p. 12. Archived from the original (PDF) on 13 January 2012. Retrieved 5 July 2011.