Book 20, Number 20.6.23:

Yahya related to me from Malik from Abdullah ibn Dinar that Abdullah ibn Umar said, "The Messenger of Allah, may Allah bless him and grant him peace, told the people of Madina to enter ihram at Zhu 'l-Hulayfa, the people of Syria to do so at al-Juhfa, and the people of Najd to do so at Qarn.'