Bangladesh, Bhutan, Cambodia, China (mainland), Hong Kong (China) (B), India, Japan, Laos, Mongolia (B), Myanmar, Nepal, North Korea (B), Pakistan, Philippines, Russia (Asian), Russia (Central Asian), South Korea, Sri Lanka, Taiwan (China), Thailand, USA, Vietnam.
Vagrant to Guam, Northern Mariana Islands.
Population
Estimated population is 910,000 - 1,800,000 (2010).
poecilorhyncha Forster, 1781 - Throughout Indian Subcontinent and east to western Assam.
zonorhyncha Swinhoe, 1866 - South-eastern USSR, Sakhalin and Japan to southern China. Considered by some authors to be a distinct species, Chinese Spot-billed Duck (Anas zonorhyncha).
haringtoni (Oates, 1907) - Eastern Assam and Burma east to southern China and Laos.