Třinec is a statutory city in Frýdek-Místek District, Moravian-Silesian Region of the Czech Republic. It lies on the Olza River, in the historical region of Cieszyn Silesia. The town has approximately 35,000 inhabitants and is the smallest statutory city in the Czech Republic. In the 2001 census, 17.7% of the population were Poles. The town is notable for its steel plant, the Třinec Iron and Steel Works, the largest in the Czech Republic, which still has a major impact on the town, on its character, demographics, and air quality.