The Town of St. Armand is in the northwestern part of the county and is southwest of Plattsburgh.
The town was first settled around 1829. The early industry was based on lumber production. After most of the trees were harvested, farming became predominant.
The town was set off from the Town of Wilmington in 1844.
By the end of the 19th Century, the town became the locale for sanatoriums intended for tuberculosis (TB) cures. Dr. Edward Trudeau in 1884 was one of the first to establish a sanatorium within the town, near the Village of Saranac Lake.