Kattegat

The Kattegat () is a sea of roughly 24,000 km2 (9,300 sq mi) bounded by the Skagerrak in the north, Jutland in the west, the Danish Straits and Zealand in the south and the Swedish provinces of Bohuslän, Västergötland, Halland and Scania in the east. The Baltic Sea drains into the Kattegat through the Danish Straits. The Kattegat is rather shallow and can be dangerous to navigate due to many sandy, stony reefs and the tricky shifting currents. In modern times, artificial seabed channels have been dug, many reefs have been dredged either by sand pumping or boulder clearance, and a well-developed light signaling network has been installed to protect the heavy international traffic on the small sea. There are several large cities and major ports on the Kattegat, including, in descending size, Gothenburg, Aarhus, Aalborg, Halmstad, Varberg and Frederikshavn.