Karptjärn is a lake in Stockholm County, Södermanland, Sweden.

Karptjärn
Location of lake
Location of lake
Karptjärn
LocationTyresö Municipality
Coordinates59°14.80′N 18°17.12′E / 59.24667°N 18.28533°E / 59.24667; 18.28533
Basin countriesSweden