Breeds central Mongolia and south-eastern Russia (south-western Transbaikalia east to lower R Amur) south to northern and eastern China (eastern from eastern Xinjiang, south to Fujian), Korea, Sakhalin I and Japan. Non-breeding mainly south-eastern Asia to Greater Sundas, Philippines and Wallacea.
 
Population
Estimated population is unknown (2012).
Often considered conspecific with Great Reed-Warbler (Acrocephalus arundinaceus). However, recent studies support treatment as distinct species, and suggest also that it is more likely to have derived from Clamorous Reed-Warbler (Acrocephalus stentoreus).
The Field Guide to the Birds of Australia Pizzey, G., and Knight, E., 1997, Angus & Robertson, Sydney ISBN 0 207 19691 5
Field Guide to Australian Birds Morecombe, M., 2000, Steve Parish Publishing Pty Ltd. ISBN 1 876282 10 X
Field Guide to the Birds of Australia Simpson, K., and Day, N., 1999, 6th Edition, Viking ISBN 0 670 87918 5
Reader's Digest Complete Book of Australian Birds 1988, 2nd Edition, Reader's Digest ISBN 0 949819 99 9
What Bird is That? 1984, Revised Edition, Angus & Robertson, Sydney ISBN 0 207 14846 5
Handbook of Australian, New Zealand & Antarctic Birds 1990 - , Oxford University Press, Melbourne ISBN 0 19 553244 9