The Messenger of Allah ﷺ said, "All of Arafah is a place of standing, but keep clear of the valley of Uranah. All of Muzdalifa is a place of standing, but keep clear of the valley of Muhassir. And all the ravines of Mina are places of sacrifice."
قال رسول الله ﷺ: عرفة كلها موقف، وارفعوا عن بطن عرنة، والمزدلفة كلها موقف، وارفعوا عن بطن محسر، وشعاب منى كلها منحر.
Tahawi reported it in Sharh Mushkil Athar (1194) from Ishaq bin Ibrahim bin Yunus Baghdadi, who said, Abu Ashath Ahmad bin Miqdam Ajli narrated to us, who said, Ibn Uyayna narrated to us, from Ziyad bin Saad, from Abu Zubayr, from Abu Mabad, from Ibn Abbas, and he mentioned it. Its chain is hasan because of Abu Ashath Ahmad bin Miqdam Ajli, for he is one whose hadith is hasan.Bazzar reported it in Kashf Astar (1127) from Hawthara bin Muhammad Minqari, from his book, Sufyan bin Uyayna narrated to us, from Amr bin Dinar, from Tawus, from Ibn Abbas, as a raised report, "Arafah in its entirety is a standing place, and Mina in its entirety is a standing place." He said, Ahmad bin Abdah also narrated to us, Sufyan bin Uyayna informed us, and he mentioned it from Tawus as a mursal report.Bazzar said, "We do not know of anyone who said 'from Ibn Abbas' except Hawthara, and he has no corroborator." End of quote.I say, it is as he said, but the route of Ahmad bin Miqdam, from Ibn Uyayna, as mentioned earlier, strengthens it.