High Quality Content by WIKIPEDIA articles! The Seward Peninsula is a large peninsula on the western coast of the U.S. state of Alaska. It projects about 320 kilometers (200 mi) into the Bering Sea between Norton Sound, the Bering Strait, the Chukchi Sea, and Kotzebue Sound, just below the Arctic Circle. The entire peninsula is about 330 kilometers (210 mi) long and 145 km (90 mi)-225 km (140 mi) wide.The Seward Peninsula was once part of the Bering land bridge, a roughly thousand mile wide swath of land connecting Siberia with mainland Alaska during the Pleistocene Ice Age.