Ahorn was first mentioned in 1074/75 as "clearing farms in the forests of Ahorny Castle".

The development of the settlement is closely related to the history of Ahorn castle, which was built in 1555 by Joachim von Rosenau after the German Peasants' War (1524–1526) on the remains of an older castle in the Renaissance style.

Since the early 1820s, Ahorn castle is owned and inhabited by a branch of the Franco-Thuringian von Erffa family.

The colors green and silver of maple leaf and castle indicate the affiliation of the municipality to the former Wettin Duchy of Saxe-Coburg and Gotha.

Maple leaf and castle are embedded in the colors gold and blue from the coat of arms of the family of the barons of Erffa.