Sunan an-Nasa'i, Book 28, Hadith 23 (In-Book)

It was narrated from Ibn 'Umar that the Messenger of Allah organized a horse race and sent them from Al-Hafya' and its finish line was Thaniyyat Al-Wada'; and he organized a race for horses that had not been made lean, and the course stretched from Ath-Thaniyyah to the Masjid of Banu Zuraiq.

أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم سَابَقَ بَيْنَ الْخَيْلِ يُرْسِلُهَا مِنَ الْحَفْيَاءِ وَكَانَ أَمَدُهَا ثَنِيَّةَ الْوَدَاعِ وَسَابَقَ بَيْنَ الْخَيْلِ الَّتِي لَمْ تُضْمَرْ وَكَانَ أَمَدُهَا مِنَ الثَّنِيَّةِ إِلَى مَسْجِدِ بَنِي زُرَيْقٍ ‏.‏

sunnah.com