Adam Clarke on Exodus 14:2

Encamp before Pi-hahiroth - פי ההירת pi hachiroth, the mouth, strait, or bay of Chiroth. Between Migdol, מגדל migdol, the tower, probably a fortress that served to defend the bay. Over against Baal-zephon, בעל צפן baal tsephon, the lord or master of the watch, probably an idol temple, where a continual guard, watch, or light was kept up for the defense of one part of the haven, or as a guide to ships. Dr. Shaw thinks that chiroth may denote the valley which extended itself from the wilderness of Etham to the Red Sea, and that the part in which the Israelites encamped was called Pi-hachiroth, i.e., the mouth or bay of Chiroth. See his Travels, p. 310, and his account at the end of Exodus.