Lesser scaup are an American species of diving duck. They breed in interior boreal forests and parklands of Alaska and Canada and into the United States in North and South Dakota, Montana, Wyoming, northeastern Washington, and the Klamath region of southern Oregon and northeastern California. In winter they are found in appropriate habitat in the Pacific coastal states, the southern states, including Colorado, the southeast, Florida, and along the Atlantic coast to Massachusetts. They are also found in the southern Great Lakes region and Ohio and Mississippi river drainages. Lesser scaup also winter throughout Mexico and Central America, the Antilles, and the Hawaiian Islands. Occasional birds are seen in winter in the western Palearctic, Greenland, British Isles, Canary Islands, and the Netherlands.

Biogeographic Regions: nearctic (Native ); neotropical (Native )