Harrietstown is a town in Franklin County, New York, United States.

[3] Harrietstown is in the southeastern corner of Franklin County and is south of the town of Brighton.

At the end of the 19th century, it became the location for sanatoria for the treatment of lung diseases, taking advantage of the clear mountain air.

[4] Harrietstown is inside the Adirondack Park and is the largest town by area in Franklin County.

The village of Saranac Lake is on the eastern border of the town, primarily in Harrietstown but extending east into the towns of St. Armand and North Elba in Essex County.

New York State Route 186 connects NY-3 to NY-86 in the northern part of the town.

39.1% of all households were made up of individuals, and 14.3% had someone living alone who was 65 years of age or older.