Častkov (Hungarian: Császkó) is a village and municipality in Senica District in the Trnava Region of western Slovakia.

In historical records the village was first mentioned in 1394.

The municipality lies at an altitude of 280 metres and covers an area of 13.182 km2.

The records for genealogical research are available at the state archive "Statny Archiv in Bratislava, Slovakia" Media related to Častkov at Wikimedia Commons

This Trnava Region geography article is a stub.