Two years later, he was sent to the New Caledonia Fur District in now north-central British Columbia, and was, at different times, in charge of Forts Chilcotin, Babine, and McLeod.

McLean was appointed Chief Trader in 1853, taking charge of Thompson's River Post (today's Kamloops) in 1855, expanding its cattle and horse herds and managing unruly relations with indigenous peoples sternly, acquiring a reputation both for fairness and severity.

He now moved there with his family, ranching, prospecting, and running a roadhouse on the Cariboo Road at Lower Hat Creek (now a heritage museum and visitor attraction).

On July 17, 1864, as McLean opened his steel mesh vest to cool off Nezunlhtsin, a Tsilhqot'in warrior, shot and killed him.

Allen, his brothers and Alex Hare were captured and brought to the British Columbia Penitentiary for trial by Chief Justice Matthew Baillie Begbie (who had also tried Klattasine), were convicted in 1879 and hung for murder in 1881.

Alexander McLean, Donald's youngest son with his first wife, Ali, owned and ran Black Pine Ranch in northern Kamloops, British Columbia.