As for the birthplace of Onsen-manju, someone says it was Gunma Prefecture, and someone says it was Ikaho-onsen hot springs, however there is no evidence that similar manju had not existed before that.
温泉饅頭の発祥地は、群馬県説、伊香保温泉説などが言われているが、それ以前に類似のものがなかったという証拠はない。