It is narrated from Tawus (may Allah have mercy on him) that Sayyiduna Mu'adh (may Allah be pleased with him) ruled: Any man who moves from the district of his clan to a district other than his clan's, his tithe ('ushr) and his sadaqah belong to the district of his clan.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13141