Located on the Flaxman Island, a barrier island on the Arctic coast of the state of Alaska, is the historic site of the Leffingwell Camp Site. It was built in the early 1900s by the polar explorer and geologist Ernest de Koven Leffingwell.

The Leffingwell Camp Site is historically significant for its participation in the Beaufort Sea exploration known as the 1906 Anglo-American Polar Expedition led by Leffingwell. The trip has helped create the first accurate map of a portion of the Alaska coastline made by the explorer himself. Leffingwell also became the first to scientifically describe permafrost that helped prove theories of permafrost.

The Leffingwell Camp Site was named a National Historic Landmark in 1978 despite its historic integrity being diminished in the 1930s.