- This article is for the sound in Alaska, United States. For the sound in British Columbia, Canada, see Frederick Sound (Canada).
Frederick Sound (also called Prince Frederick Sound or Prince Frederick's Sound) is a passage of water in the Alexander Archipelago in Southeast Alaska that separates Kupreanof Island to the south from Admiralty Island in the north.
Frederick Sound was named by Captain George Vancouver for Prince Frederick, Duke of York and Albany. It was first charted in 1794 by two of his men, Joseph Whidbey and James Johnstone. The sound may also be known as the Russian transliteration Fridrikhe Zund.
The sound is home to the Five Finger Islands Light.
- Vancouver, George, and John Vancouver (1801). A voyage of discovery to the North Pacific ocean, and round the world. London: J. Stockdale.