“encamped at Gilgal.” The exact site of Gilgal has not been located, but given the size of the Israelite camp, “Gilgal” might have been properly the place where the Tent of Meeting and ark of God camped, with Israel camped around it as they did in the wilderness. Gilgal had not been a city, it was the place where Israel camped.
“on the 14th day of the month at evening.” The Hebrew day started at sunset, making this 40 years to the day of when the children of Israel ate the Passover and then left Egypt after midnight. (Exod. 12:29-37).