A fjord is a long, deep, narrow body of water that reaches far inland. Fjords are often set in a U-shaped valley with steep walls of rock on either side. Fjords are found mainly in Norway, Chile, New Zealand, Canada, Greenland, and the U.S. state of Alaska. Sognefjorden, a fjord in Norway, is more than 160 kilometers (nearly 100 miles) long. Fjords were created by glaciers. In the Earth's last ice age, glaciers covered just about everything. Glaciers move very slowly over time, and can greatly alter the landscape once they have moved through an area. This process is called glaciation. Glaciation carves deep valleys. This is why fjords can be thousands of meters deep. Fjords are usually deepest farther inland, where the glacial force was strongest. Some features of fjords include coral reefs and rocky islands called skerries

https://www.nationalgeographic.org/encyclopedia/fjord/

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