Musnad Ahmad 27:638

Isma'il narrated to us, Ayyub informed us, from Nafi', from Ibn 'Umar, who said: A man said: "O Messenger of Allah, from where should we enter into Ihram?" He said: "The people of Medina enter into Ihram from Dhu al-Hulayfah, the people of Syria from al-Juhfah, and the people of Najd from Qarn." He said: And they say: "And the people of Yemen from Yalamlam."