Allagash is a town in Aroostook County, Maine, United States.

[1] This makes Allagash the largest town in Maine in terms of total land area (although when both land and water areas are included in the total, then Vinalhaven and St. George (both in coastal Knox County) are larger than Allagash).

About 15.1% of families and 18.8% of the population were below the poverty line, including 27.3% of those under the age of eighteen and 23.5% of those 65 or over.

The racial makeup of the town was 97.5% White, 0.4% African American, and 2.1% from two or more races.

35.5% of all households were made up of individuals, and 15.3% had someone living alone who was 65 years of age or older.