The Prophet ﷺ's hair used to reach down to his shoulders.
أخبرنا محمد بن معمر قال حدثنا حبان قال حدثنا همام عن قتادة
أن النبي ﷺ كان يضرب شعره إلى منكبيه
No references are available.
Bukhari transmitted it, Clothing, chapter on curly hair, no. 5903, 5904, and Muslim, Virtues, chapter on the description of the Prophet's ﷺ hair, no. 95/2338, from the hadith of Habban bin Hilal, through the same chain.