Al-Walid bin Muslim (may Allah have mercy on him) says: I asked Abu Amr (may Allah have mercy on him): From where should a person walk who is obliged to walk to the House of Allah? (He said:) If he intended a particular place, then he should walk from there; otherwise he should walk from the appointed miqat.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النذور / 20132