The last complete sura revealed (in the Holy Qur'an) is Sura Tauba (i e. al-Bara'at, ix.), and the last verse revealed is that pertaining to Kalala.
أَنَّ آخِرَ سُورَةٍ أُنْزِلَتْ تَامَّةً سُورَةُ التَّوْبَةِ وَأَنَّ آخِرَ آيَةٍ أُنْزِلَتْ آيَةُ الْكَلاَلَةِ
The last verse revealed (in the Holy Quran) is that pertaining to Kalala, and the last sura revealed is Sura al-Bara'at.
سَمِعْتُ الْبَرَاءَ بْنَ عَازِبٍ يَقُولُ آخِرُ آيَةٍ أُنْزِلَتْ آيَةُ الْكَلاَلَةِ وَآخِرُ سُورَةٍ أُنْزِلَتْ بَرَاءَةُ
The last Verse that was revealed was: 'They ask you for a legal verdict: Say: Allah directs (thus) about Al-Kalalah (those who leave no descendants or ascendants as heirs).' And the last Sura which was revealed was Baraatun (9) . (Using translation from Bukhārī 4654)
سَمِعْتُ الْبَرَاءَ يَقُولُ «آخِرُ آيَةٍ نَزَلَتْ آيَةُ الْكَلَالَةِ وَآخِرُ سُورَةٍ نَزَلَتْ بَرَاءَةٌ»