The Danubian Lowland reaches the region to Nové Mesto nad Váhom and Partizánske areas.

The population density is 129/km2 (330/sq mi) (2020-06-30/-07-01),[5] which is more than Slovak average (110 per km2), and the second highest after the Bratislava Region.

The largest towns are Trenčín, Prievidza, Považská Bystrica, Dubnica nad Váhom and Partizánske.

According to the 2001 census, the region had 605,583 inhabitants, with Slovaks forming a relatively homogeneous majority (97.3%), with a small minority of Czechs (1%) and others.

In election 2022 was elected also regional parliament : The Trenčín Region consists of 9 districts: Bánovce nad Bebravou, Ilava, Myjava, Nové Mesto nad Váhom, Partizánske, Považská Bystrica, Prievidza, Púchov, and Trenčín.