Following the construction of the Canadian Pacific Railway (CPR), increased settlement on the Cariboo Plateau south of the goldfields region shifted the population weight of the riding to that area, which was increasingly centred on the town of Williams Lake and the plateau between there and Kamloops, British Columbia. The southern Cariboo region, later added in a redistribution and division of the Cariboo riding into Cariboo South and Cariboo North, which exist today, was originally part of the Lillooet riding. The Lillooet and Cariboo provincial ridings combined formed the original definition of the Cariboo federal riding.