Sahih Bukhari, Chapter: Pilgrimage (Hajj)

Allah's Apostle (p.b.u.h) made Dhul-Hulaifa as the Miqat for the people of Medina; Al-Juhfa for the people of Sham; Qarn-al-Manazil for the people of Najd; and Yalamlam for the people of Yemen; and these Mawaqit are for the people at those very places, and besides them for those who come through those places with the intention of performing Hajj and Umrah; and whoever is living within these boundaries can assume ihram from the place he starts, and the people of Makkah can assume ihram from Makkah.