[2] Early settlers moved to what would become Cyr Plantation in the mid-1800s, then known as Township Letter L. Around that time, a road was built between the Aroostook River and Grand Falls, New Brunswick, Canada (which today stretches between Caribou, Maine, and Hamlin, Maine).

Many early inhabitants obtained grants to lots near the road and Hammond Brook to farm the land.

[3] According to the United States Census Bureau, the plantation has a total area of 99.3 square kilometres (38.3 sq mi), all land.

There were 51 housing units at an average density of 1.3 per square mile (0.5/km2).

There were 12.5% of families and 9.9% of the population living below the poverty line, including 5.0% of under eighteens and none of those over 64.