The part of Denmark that is closest to Sweden is the region of Skåne.
Specifically, the town of Helsingør in Denmark is only about 4 kilometers (approximately 2.5 miles) from the Swedish town of Helsingborg. This narrow strait, known as the Öresund, separates the two countries and is a crucial maritime route.
Additionally, the Öresund Bridge, which connects Copenhagen in Denmark to Malmö in Sweden, further facilitates travel between the two nations. The bridge spans about 8 kilometers (5 miles) across the strait, making it a significant link for both transportation and commerce.