Ibn Ishaq (may Allah have mercy on him) said: the Messenger of Allah (peace and blessings be upon him) proceeded on, and when he came out of the pass called al-Safra', he went from there towards the sand dune called Sayr, which is at a distance of one night's journey from Badr, or more. Then he (peace and blessings be upon him) divided the spoils at that dune.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17983