The Nile and Tigris River very both very important to the early civilizations of their geographical regions.  The Nile River supported farming and trade for the Ancient Egyptians while the Tigris River was one of two rivers that provided the same advantage for the Sumerians.  The Nile River is much longer than the Tigris River.  The Nile is over 4,000 miles long while the Tigris River is only 1,150 miles long.  Another difference between the rivers is inundation.  This was an important distinction for the two civilizations.  A major benefit of the Nile River was that its floods were not generally destructive to the civilizations that it supported.  The flooding was as gradual as it was predictable.  The flooding of the Tigris River was very unpredictable and it often caused great destruction. For this reason, the rivers of Mesopotamia were both a blessing and a curse to the ancient civilizations.  The direction of the rivers is also different as the Tigris River flows northwest to southeast while the Nile River flows from south to north.