Sunan an-Nasa'i, Hadith 5235 ⓘ
It was narrated from Anas that: The hair of the Prophet [SAW] came down to his shoulders.
أَخْبَرَنَا مُحَمَّدُ بْنُ مَعْمَرٍ، قَالَ حَدَّثَنَا حَبَّانُ، قَالَ حَدَّثَنَا هَمَّامٌ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَضْرِبُ شَعْرُهُ إِلَى مَنْكِبَيْهِ .
also referenced under: Book 48, Hadith 196 (In-Book) & Volume 6, Book 48, Hadith 5237 (DarusSalam)