This town was formed from parts of Walpole and Charlestown and incorporated in 1787. It is named for N.H. Gov. John Langdon, who served in the Continental Congress and as a senator.

An agricultural town, it has been noted for its large, handsome cattle and fine farms.

Rev. Abner Kneeland, who was ordained at the Universalist Church here in 1805, was one of the leading men of that denomination in New England, and the church here was one of the largest in the state by 1853.