Karviná is a city in Moravian-Silesian Region of the Czech Republic, on the Olza River. It is administrative center of Karviná District. Karviná lies in the historical region of Cieszyn Silesia and is one of the most important coal mining centers in the Czech Republic. Together with neighboring towns it forms industrial Ostrava-Karviná Coal Basin. Polish population is historically declining. In the past the town had a significant German community. There is also a growing Romani community.