Karsträsk is a village in Skellefteå Municipality, in Västerbotten County, Sweden. Karsträsk lies at 199 m above sea level. The nearest city is Skellefteå, 39 km to the east. Among the landmarks around are Bolidens kyrka (12.4 km), Petiknäs Church (14.4 km) and Kalvträsks kyrka (24 km).