Thomas Square is a park in Honolulu, Hawaii, named for Admiral Richard Darton Thomas. The Privy Council voted to increase its boundaries on March 8, 1850, making Thomas Square Hawaii's oldest city park. It is one of four sites in Hawaii where the Hawaiian flag is allowed to fly alone without the United States flag.

Admiral Richard Darton Thomas was an officer of the British Royal Navy who served during the French Revolutionary and Napoleonic Wars, and went on to become Commander-in-Chief, Pacific Station in the 1840s.