Afghanistan, northern India: known from type locality near Rampur, in Sutlej Valley (Himachal Pradesh). Very recently, a bird trapped in south-central Thailand.
 
Population
Estimated population is unknown (2010).
Large-billed Reed Warbler (Acrocephalus orinus) [XC734093]
by Ding Li Yong from R\u016dshan, Rushon, Gorno-Badakhshan Autonomous Province, Tajikistan (subsong)
Large-billed Reed Warbler (Acrocephalus orinus) [XC734095]
by Ding Li Yong from R\u016dshan, Rushon, Gorno-Badakhshan Autonomous Province, Tajikistan (subsong)
Subspecies
No subspecies.
Until recently it was known only from one specimen, collected in the Sutlej Valley near Rampoor, Himachal Pradesh, India in November 1867. In March 2006 one was trapped at Laem Phak Bia, Phatchaburi Province, south-west Thailand, and in April 2007 a bird apparently of this species was observed and photographed near Chintamani Kar Bird Sanctuary, Narendrapur, West Bengal, India. Estimated population is unknown (2010).
Acrocephalus stentoreus (Sibley and Monroe 1990, 1993) has been split into Clamorous Reed-Warbler (Acrocephalus stentoreus) and Large-billed Reed-Warbler (Acrocephalus orinus) following Bensch and Pearson (2002).