Komárno, colloquially also called Révkomárom, Öregkomárom, Észak-Komárom in Hungarian, is a town in Slovakia at the confluence of the Danube and the Váh rivers. Historically it was formed by the "old town" on the left bank of Danube, present day Komárno in Slovakia, and by a "new town" on the right bank, present day Komárom in Hungary, which were historically one administrative unit. Following World War I and the Treaty of Trianon, the border of the newly created Czechoslovakia cut the historical, unified town in half, creating two new independent towns in two countries. Komárno and Komárom are connected by the Elisabeth Bridge, which used to be an official border crossing between Slovakia and Hungary until border checks were lifted due to the Schengen Area rules. In 2020, a new road bridge was opened.

The Váh is the longest river within Slovakia. Towns on the river include Liptovský Hrádok, Liptovský Mikuláš, Ružomberok, Vrútky, Žilina, Bytča, Považská Bystrica, Púchov, Ilava, Dubnica nad Váhom, Nemšová, Trenčín, Nové Mesto nad Váhom, Piešťany, Hlohovec, Sereď, Šaľa, Kolárovo and Komárno.