Black River-Hardwicke was a local service district in Northumberland County, New Brunswick. It is now part of the Greater Miramichi rural district.
In the 2021 Census of Population conducted by Statistics Canada, Black River-Hardwicke had a population of living in of its total private dwellings, a change of from its 2016 population of . With a land area of , it had a population density of in 2021.