Baldwin Peninsula is a peninsula located on the Arctic Circle in the northwestern region of the U.S. state of Alaska, at . It extends 72 km (45 mi) into Kotzebue Sound from the Alaska mainland and defines the south boundary of Hotham Inlet. It is 2–19 km (1–12 miles) wide.
The city of Kotzebue and Ralph Wien Memorial Airport are located at the end of the peninsula. The remainder of the peninsula is covered with permafrost and hundreds of tundra lakes.