Range of caribou in North America. Background colours show the ranges of the four subspecies (R. t. caribou; R. t. groenlandicus; R. t. pearyi; R. t. granti). Circles and triangles indicate sampling locations for this study and are coloured by designatable unit. We also included two genomes from Greenland shown by the black circles. A circle indicates that the sample is from the BEL mitochondrial lineage and a triangle means the sample is from the NAL mitochondrial lineage. Sample numbers 1 and 2 are from the Yukon Porcupine herd, 3 and 4 from the Northwest Territories Bluenose herd, 5 and 6 from the Manitoba Qamanirijuaq herd, 7 and 8 from Western Greenland Kangerlussuaq, 9 and 10 from the Northwest Territories Sahtú region, 11 and 12 from the Manitoba Naosap herd, 13 from Ontario Ignace 14 from Ontario Cochrane, 15 and 16 from the Ontario Pen Island herd, 17 and 18 from the Quebec George River herd, 19 and 20 from the Northwest Territories, Redstone herd, 21 and 22 from the British Columbia Atlin herd, 23 and 24 from the British Columbia Frog herd, 25 and 26 from the British Columbia Itcha‐Ilgachuz herd, 27 and 28 from Nunavut Bathurst Island and 29 and 30 from the British Columbia Columbia North herd[Colour figure can be viewed at wileyonlinelibrary.com]