Table 1. Orangutan records, most likely P. tapanuliensis, but outside the current range, that we consider to be reliable.

Number	Location	Source	Information type	Vegetation/Elevation	Likely status
1 a	Angkola	Tulp 1641	Specimen seen by author	Hill forest <750m	Breeding population
2 a	Kampar Regency	Müller 1837	Anecdotal	Dryland forest <750m	Unclear
3	Around Bukittinggi	Anonymous 1842	Anecdotal	Hill forest <750m	Unclear
4	Between Fort de Kock and Bonjol	Anonymous 1842	Anecdotal	Hill forest <750m	Unclear
5	Bukit Gedang	Ludeking 1862	Anecdotal	Sub-montane forest >750m	Roaming male
6	Tapanuli	Von Rosenberg 1878	Anecdotal or seen by author	Dryland forest <750m	Breeding population
7	Sayur Matinggi	Kramm 1879	Seen by author	Hill forest >750m	Breeding population
8	Lumut	Kramm 1879	Seen by author	Tall Peat swamp forest <750m	Breeding population
8	Lumut	Nests observed by Serge Wich and Tine Geurts in June 2001	Seen by author	Tall Peat Swamp forest <750m	Breeding population
8	Nests near Lumut	Nests observed by Serge Wich and Tine Geurts in June 2001	Seen by author	Tall Peat Swamp forest <750m	Breeding population
9	Hadjoran	Neumann 1885	Anecdotal	Hill forest >750m	Roaming male
10	Batang Nilo	L.H. 1888	Anecdotal	Freshwater swamp forest <750m	Unclear
11	Lake Maninjau	Twiss 1890	Anecdotal	Hill forest >750m	Unclear
12	Bukit Silajang	Twiss 1890	Anecdotal	Sub-montane forest >750m	Unclear
13	West Coast	Hagen 1890	Anecdotal + reference to specimen	Hill forest <750m	Unclear
14	Jaga Jaga	Miller 1903	Anecdotal	Freshwater swamp forest <750m	Breeding population
15	Berdiri River	Miller 1903	Anecdotal	Dryland forest <750m	Breeding population
16	Upland areas west of Lake Toba	Volz 1912	Unclear, probably anecdotal	Sub-montane forest >750m	Breeding population
17	Kualu River	Volz 1912	Anecdotal	Dryland forest <750m	Roaming male
18	Talu	Captain H.G.C. Pel 1935	Seen by author	Hill forest >750m	Unclear
19	Rimbu Panti	Meijaard 1997	Anecdotal	Hill forest <750m	Unclear
20	Talamau Mountain	Laumonier 1983	Seen by author	Montane forest >750m	Unclear
21	Bhara Induk logging base camp	Meijaard 1997	Anecdotal	Dryland forest <750m	Roaming male
22	South of Batang Toru	Orangutan observed by Martin Jones in 2004	Seen by author	Dryland forest <750m	Unclear
23	Barumun	Kuswanda 2014	Anecdotal	Sub-montane forest >750m	Unclear

^a Point numbers in the table correspond to the numbers in Fig 1. Vegetation information was derived from Laumonier [29]. The 750m contour was obtained from the NASA SRTM Digital Elevation Model data [36].