Sosnowiec is a city located in the south of Poland. A county capital neighbouring Katowice, and a mining and industrial region, it was one of the largest cities in the Silesian Voivodeship and Upper Silesian Industry Area. Sosnowiec belongs to Zagłębie Dąbrowskie, and not to Silesia. Its population as of 2006 numbers 225,202.

It is sometimes known by the names Sosnowietz, Sosnowitz, Sosnovitz (Yiddish), Sosnovyts, Sosnowyts, Sosnovytz, Sosnowytz, Sosnovets (Russian), Sosnovetz. There are 5 other smaller towns in Poland also called Sosnowiec. They are located in the regions of Bydgoszcz, Kielce, Łódź, Łomża, and Opole.