In Latter-day Saint theology, Pharaoh is the proper name of the first king of Egypt, as found in the Book of Abraham in the Pearl of Great Price.
According to the Mormon text, Pharaoh is the son of Egyptus, daughter of Ham, son of Noah, who rules Egypt righteously during his entire reign. However, he does not have the "fullness of the gospel," and Egypt gradually degenerates to idol worship after his death. His father has been assumed to have been either Mizraim or Canaan, both brothers to Egyptus and sons to Ham, son of Noah.
Though Pharaoh was Egypt's first King, Egypt would likely have been separated into two Egypts before the birth of Mizraim, because his name means "two lands". This would mean Egyptus founded Egypt, and before the birth of her brother (Mizraim) the land became divided. Pharaoh possibly then became king of one of these lands before Mizraim (presumably) reunited these lands to form one Egypt. However it is also possible that Pharaoh reunited the country and later the land became divided again. In either situation Mizraim is bound to have done something of greater importance than his nephew (and/or son), in order for the land to end up bearing his name. There is no doubt however that Pharaoh (and his mother) were great rulers, as the term Pharaoh is named after him.