Albert Barnes Commentary Exodus 2:15

"Now when Pharaoh heard this thing, he sought to slay Moses. But Moses fled from the face of Pharaoh, and dwelt in the land of Midian: and he sat down by a well." — Exodus 2:15 (ASV)

No Egyptian king would have left such an offense unpunished. But the position of Moses, as an adopted son of a princess, made it necessary even for a despotic sovereign to take unusual precautions.

The land of Midian - The Midianites occupied an extensive district from the eastern coast of the Red Sea to the borders of Moab.