Sayyiduna Abu Tha'labah al-Khushani (may Allah be pleased with him) says: Whenever the Messenger of Allah (peace and blessings be upon him) camped at a place, the people would scatter in the valleys and mountain passes. The Messenger of Allah (peace and blessings be upon him) said: "Your scattering in these mountain passes and valleys is from Satan." After that, whenever they camped, they kept so close together that if a single sheet were spread over them, it would have been enough for them all.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18457