Kärdla (Estonian pronunciation: [ˈkærˑ'dlɑ]) (Swedish: Kärrdal, German: Kertel) is the only town on the island of Hiiumaa, Estonia. It is the capital of Hiiu County and the centre of Hiiu Parish.
Kärdla is located on the north-eastern coast of Hiiumaa, by the Tareste Bay. Southeast of the town is the Kärdla meteorite crater, which is 455 million years old. Several small rivers flow through the town. There are also artesian wells in Kärdla.
Kärdla was first mentioned in 1564 as a village inhabited by Swedes. Its growth was greatly influenced by the cloth factory founded in 1830. A port was built in 1849. Both the port and the factory were destroyed in World War II.
Kärdla officially became a borough in 1920 and a town in 1938. In 2013 the town was merged with Kõrgessaare Parish to establish Hiiu Parish, therefore Kärdla lost its municipality status.
Road transport from Estonian mainland to Hiiumaa involves a 90-minute (28 km (17 mi)) ferry crossing from Rohuküla to Heltermaa, which is 25 kilometres (16 miles) by road from Kärdla. There are about 10 ferry departures a day. In the summer weekends, getting car space on the ferry usually requires advance booking. There are about 2 scheduled buses a day between Tallinn (the capital of Estonia) and Kärdla.