Sunan an-Nasa'i, Volume 4, Book 26, Hadith 3257 (DarusSalam) ⓘ

It was narrated from 'Aishah that the Messenger of Allah married her when she was six years old, and consummated the marriage with her when she was nine.

أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا أَبُو مُعَاوِيَةَ، قَالَ حَدَّثَنَا هِشَامُ بْنُ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم تَزَوَّجَهَا وَهِيَ بِنْتُ سِتٍّ وَبَنَى بِهَا وَهِيَ بِنْتُ تِسْعٍ ‏.‏

sunnah.com

Key Source: Marriage to Aisha

Maybe one of the most controversial areas of Muhammed's life was his marriage to a child bride, Aisha. According to Muslim sources, Muhammad married her in his 50s, while she was 6 years old, and the marriage was consummated when she was 9 years old. This relationship in particular is seen...

Key Sources

Read more

also referenced under: Hadith 3255 (Reference) & Book 26, Hadith 60 (In-Book)