Trenčín is a city in western Slovakia of the central Váh River valley near the Czech border. 
The city has a medieval castle, Trenčín Castle, on a rock above the city. It is the third-largest castle in Slovakia.  Below the castle, on the hillside, is the old parish church and a small upper square which is reached by historic covered stairs as well as by winding side streets. The old town has a large main square, with a large baroque church and various shops, as well as a town tower. The Trenčín Synagogue, built in 1913 is now a cultural center with exhibitions and concerts.