From Sahih Bukhari (Hadith 4275):
Narrated Ubaidullah bin `Abdullah bin `Utba:Ibn `Abbas said, Allah's Messenger (ﷺ) fought the Ghazwa (i.e. battles of Al-Fath during Ramadan." Narrated Az-Zuhri: Ibn Al-Musaiyab (also) said the same. Ibn `Abbas added, "The Prophet (ﷺ) fasted and when he reached Al-Kadid, a place where there is water between Qudaid and 'Usfan, he broke his fast and did not fast afterwards till the whole month had passed away
Reference: Bukhari 4275