Flatlands was a local service district in Addington Parish, Restigouche County, New Brunswick, Canada. The Duncan family of Aberdeen, Scotland were the original settlers of Flatlands and Campbellton. In 1866 Flatlands was a farming and lumbering settlement with approximately 27 resident families. In 1871, it had a population of 150. In 1898 Flatlands was a station on the Intercolonial Railway and had one post office, three stores, a shingle mill, a church and a population of about 400.

Flatlands is located along the Restigouche River, opposite the Province of Quebec. It is approximately 5 km from Matapédia, Quebec, a 5-minute drive, and about 15 km from downtown Campbellton, New Brunswick, a 20-minute drive. Route 11 is the major highway running through the community, with a posted speed limit of 80 km/h.

In the 2021 Census of Population conducted by Statistics Canada, Flatlands had a population of 153 living in 78 of its 87 total private dwellings, a change of 7% from its 2016 population of 143. With a land area of 18.83 km (7.27 sq mi), it had a population density of 8.1/km (21.0/sq mi) in 2021.

Population of Flatlands

Name	Parish	Population (2021)	Population (2016)	Change	Land area (km)	Population density
Flatlands part A	Addington	148	143	+3.5%	15.71	9.4/km
Flatlands part B	Eldon	5	0	NA	3.12	1.6/km
Total	—	153	143	+7.0%	18.83	8.1/km