Pi-hahiroth
   place where the reeds grow (LXX. and Copt. read "farmstead"),
   the name of a place in Egypt where the children of Israel
   encamped (Ex. 14:2, 9), how long is uncertain. Some have
   identified it with Ajrud, a fortress between Etham and Suez. The
   condition of the Isthmus of Suez at the time of the Exodus is
   not exactly known, and hence this, with the other places
   mentioned as encampments of Israel in Egypt, cannot be
   definitely ascertained. The isthmus has been formed by the Nile
   deposits. This increase of deposit still goes on, and so rapidly
   that within the last fifty years the mouth of the Nile has
   advanced northward about four geographical miles. In the maps of
   Ptolemy (of the second and third centuries A.D.) the mouths of
   the Nile are forty miles further south than at present. (See EXODUS.)
   

Pi-hahiroth, the mouth; the pass of Hiroth