Leszno County (Polish: powiat leszczyński) is a unit of territorial administration and local government (powiat) in Greater Poland Voivodeship, west-central Poland. It came into being on January 1, 1999, as a result of the Polish local government reforms passed in 1998. Its administrative seat is the city of Leszno, although the city is not part of the county (it constitutes a separate city county). The only towns in Leszno County are Rydzyna, which lies 9 km (6 mi) south-east of Leszno, and Osieczna, 10 km (6 mi) north-east of Leszno.