Port Alberni is a city located in the province of British Columbia in Canada. It is the location of the head offices of the Alberni-Clayoquot Regional District. The city has a total population of 17,743, and a census agglomeration area of 25,396.Port Alberni is a deep port city which lies within the Alberni Valley at the head of the Alberni Inlet, Vancouver Island's longest inlet.Port Alberni is the sister-city to Abashiri, Hokkaido Prefecture in northern Japan.