Senec is a town in the Bratislava Region of south-western Slovakia. The town is the administrative seat of the Senec District and its largest m…Senec is a town in the Bratislava Region of south-western Slovakia. The town is the administrative seat of the Senec District and its largest municipality. In 2022 it had a population of over 20,000. The town is a summer tourism and recreation center well known for its summer resort Sunny Lakes and its proximity to Bratislava, the capital and largest city of Slovakia.