|• Municipal manager||Seppo Saarinen|
|• Total||259.27 km2 (100.10 sq mi)|
|• Land||246.06 km2 (95.00 sq mi)|
|• Water||13.21 km2 (5.10 sq mi)|
|• Density||10/km2 (27/sq mi)|
|Time zone||UTC+2 (EET)|
|• Summer (DST)||UTC+3 (EEST)|
It was located in the Satakunta region. The population of Köyliö was 2,665 (30 June 2015) and covered a land area of 246.06 km2 (95.00 sq mi). The population density was 10.8307/km2 (28.051/sq mi).
The municipality was unilingually Finnish.
It is said that the peasant Lalli murdered the English bishop Henry on the ice of Lake Köyliö in 1156 AD, during the first Swedish Crusade into Finland. A statue to Lalli was erected at Köyliö in 1989.
Before the 2016 consolidation, Köyliö was twinned with;
- "Area by municipality as of 1 January 2011" (PDF) (in Finnish and Swedish). Land Survey of Finland. Retrieved 9 March 2011.
- "Väestötietojärjestelmä rekisteritilanne 30.06.2015" (in Finnish and Swedish). Population Register Center of Finland. Archived from the original on 3 October 2013. Retrieved 17 July 2015.
- "Köyliön ja Säkylän kuntaliitos uuden hallituksen ensimmäisiä päätöksiä". Retrieved April 24, 2015.
- "Sõprusvallad" (in Estonian). Kõo Parish. Archived from the original on 20 July 2011. Retrieved 24 May 2010.