It came into being on January 1, 1999, as a result of the Polish local government reforms passed in 1998. Its administrative seat and largest town is Olesno, which lies 42 kilometres (26 mi) north-east of the regional capital Opole. The county contains three other towns: Praszka, 20 km (12 mi) north of Olesno, Dobrodzień, 17 km (11 mi) south of Olesno, and Gorzów Śląski, 18 km (11 mi) north of Olesno.