Hadithcore
Bulugh al-Maram, 725

Al-Bukhari reported that it was Umar, who specified Dhat 'Irq as the miqat (of those coming from Iraq).

وَفِي اَلْبُخَارِيِّ: { أَنَّ عُمَرَ هُوَ اَلَّذِي وَقَّتَ ذَاتَ عِرْقٍ } [1]‏ .‏

References2 variants
In-Book Reference
Book 6, Hadith 18
English Reference
Book 6, Hadith 744