Karlskoga is a locality and the seat of Karlskoga Municipality, Sweden. Located within Örebro County, 45 km (28 mi) west of Örebro, and 10 km (6 mi) north of Degerfors. With a 2020 population of 27,386 distributed over 10.55 square miles (27.33 km2), Karlskoga is the second-largest city in both Örebro County and the historical province of Värmland.

Örebro County is a county or län in central Sweden. It borders the counties of Västra Götaland, Värmland, Dalarna, Västmanland, Södermanland and Östergötland. It is frequently culturally divided into the hilly northern region of Bergslagen, where mining and metallurgic industry have been important since the Middle Ages, and the southern Mälardalen of lakes and farms.