It is about 240 km wide at its narrowest point and generally around 50 metres deep. It has many islands, with King Island and Flinders Island home to many towns.
The water is very rough, with many ships lost in the 19th century. A lighthouse was built on Deal Island in 1848 to help ships in the eastern part of the Straits. On the west, the Cape Otway Lighthouse was first lit in 1848. Another lighthouse was at Cape Wickham at the northern end of King Island in 1861.