Hadadrimmon

A place in the valley of Megiddo, where the good king Josiah lost his life in a battle with the Ethiopians, 2 Kings 23:29 2 Chronicles 35:20-25. The lamentation over this event was very great, Zechariah 12:11.

Source: ATS Bible Dictionary
Hadadrimmon

is, according to the ordinary interpretation of ( 12:11) a place in the valley of Megiddo (a part of the plain of Esdraelon, six miles from Mount Carmel and eleven from Nazareth), where a national lamentation was held for the death of King Josiah. It was named after two Syrian idols.

Source: Smith's Bible Dictionary