In the 2021 Census of Population conducted by Statistics Canada, Northern Arm had a population of 371 living in 166 of its 213 total private dwellings, a change of -12.9% from its 2016 population of 426. With a land area of 24.94km2 (9.63sqmi), it had a population density of 14.9/km2 (38.5/sqmi) in 2021.[1]