Language:
كتاب النكاح
67
Wedlock, Marriage (Nikaah)
(60)
Chapter: Whoever consummated his marriage with a lady of nine years of age
(59)
باب مَنْ بَنَى بِامْرَأَةٍ وَهْىَ بِنْتُ تِسْعِ سِنِينَ

Narrated 'Urwa:

The Prophet (ﷺ) wrote the (marriage contract) with `Aisha while she was six years old and consummated his marriage with her while she was nine years old and she remained with him for nine years (i.e. till his death).

حَدَّثَنَا قَبِيصَةُ بْنُ عُقْبَةَ، حَدَّثَنَا سُفْيَانُ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ عُرْوَةَ، تَزَوَّجَ النَّبِيُّ صلى الله عليه وسلم عَائِشَةَ وَهْىَ ابْنَةُ سِتٍّ وَبَنَى بِهَا وَهْىَ ابْنَةُ تِسْعٍ وَمَكَثَتْ عِنْدَهُ تِسْعًا‏.‏
Reference : Sahih al-Bukhari 5158
In-book reference : Book 67, Hadith 93
USC-MSA web (English) reference : Vol. 7, Book 62, Hadith 88
  (deprecated numbering scheme)