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. The plantation was formally organized on March 12, 1870, and named after the many Cyrs in the area, including Andre Cyr and his father Christopher, the first Cyrs in Cyr Plantation.

In 1879, the settlement was principally on the stagecoach-line from Caribou to Van Buren (Maine), known as Caribou Road. Throughout the century, there were people living on rear lots of the Cyr Plantation. At one time, two sawmills and a starch factory were in operation. Today Cyr Plantation is a full township with an area of approximately 6.5 square miles. The township with its reddish soil, yields good crops of wheat, oats, buckwheat, and its famous potatoes!