It is narrated from Nafi‘ that when Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) would leave Madinah for Makkah for Hajj or ‘Umrah, he would shorten the prayer starting from Dhu’l-Hulayfah.

It is narrated from Hazrat Salim bin Abdullah that his father, Sayyiduna Abdullah bin Umar (may Allah be pleased with them), set out from Madinah riding to go to Raym, so he shortened the prayer on the way.
Imam Malik (may Allah have mercy on him) said: Raym is at a distance of four barid from Madinah.

It is narrated from Hazrat Salim bin Abdullah that Sayyiduna Abdullah bin Umar (may Allah be pleased with them) once rode from Madinah to Dhat al-Nusub and shortened the prayer on the way.
Imam Malik (may Allah have mercy on him) said: Dhat al-Nusub is four burd from Madinah.

Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) used to shorten the prayer when traveling from Madinah to Khaybar.

It is narrated from Hazrat Salim bin Abdullah that Sayyiduna Abdullah bin Umar (may Allah be pleased with them) used to shorten the prayer for the distance of a full day's journey.

Nafi' used to travel with Sayyiduna Abdullah bin Umar (may Allah be pleased with them both), and for a distance of one barid, he would not shorten the prayer.

It reached Imam Malik, may Allah have mercy on him, that Sayyiduna Abdullah bin Abbas, may Allah be pleased with them both, used to shorten the prayer for a distance as much as that between Makkah and Ta’if, and as much as that between Makkah and Usfan, and as much as that between Makkah and Jeddah.

Imam Malik, may Allah have mercy on him, said: I like very much, in the matter of shortening (the prayer), and all these distances are four barid each.

Imam Malik, may Allah have mercy on him, said: A traveler should not shorten the prayer until he has left the inhabited area of the city, and he should not stop shortening the prayer until he enters the inhabited area of the city or comes close to it.