When we read in Genesis 6–9, it is obvious that there was a global Flood. So, the alleged contradiction is that some pre-Flood place names reappear after the Flood. For example, Table 1 illustrates the most common ones:

Table 1. Pre-Flood and Post-Flood References

Name Bible Reference Pre-Flood Bible reference Post-Flood Person
Havilah Genesis 2:11 Genesis 10:7, 29 Noah’s grandson through Ham; Noah’s great, great, great, great grandson through Shem
Cush Genesis 2:13 Genesis 10:6 Noah’s grandson through Ham
Asshur Genesis 2:14 (NIV) Genesis 10:22 Noah’s grandson through Shem
Tigris Genesis 2:14 (NIV) Genesis 10:4 River in modern-day Iraq
Euphrates Genesis 2:14 Genesis 15:18 River in modern-day Iraq

The answer to this conundrum is quite simple, but let’s use some illustrations so that we can better understand this.

  1. Names of places often transfer. For example, Versailles, Illinois, was named for Versailles, Kentucky, when settlers moved from Kentucky into Illinois. And before that Versailles, Kentucky, was named for Versailles, France. If someone said to meet me in Versailles, you may have to ask “which one?”
  2. Names of places often come from names of people as well. The land of Canaan was named form Noah’s grandson Canaan. St. Louis, Missouri, was named for King Louis IX of France.
  3. Names of people sometimes came from places. Consider the name London that many people today have and its origin as a city in England.

With this in mind, it should be fairly easy to see how names could easily have been transferred through the Flood. Ham’s grandson was likely named after the land of Havilah. Cush was Ham’s son, and Asshur was Shem’s son. Noah, Ham, and Shem lived before the Flood and would have been aware of these regions. And, of course, these names have gone on to become names of regions where some of these people settled after the dispersal of the Tower of Babel. Cush is modern-day Ethiopia; Asshur was where Assyria developed into a great nation and so on.

For example, if I were to mention the “Thames River,” most people would quickly think of a river in southern England. However, the state of Connecticut in the U.S. and Ontario, Canada, also have a river named Thames. When people settled in the Americas from Europe, they named some of these rivers for rivers they were familiar with. Why would we expect Noah and his descendants to do any differently. The Tigris and Euphrates that we know today in modern day Iraq were named for the famous headwaters in the Garden of Eden.

There is no contradiction, but merely a situation of renaming new places, rivers, and people with previously used names.  http://www.answersingenesis.org/articles/2009/03/23/contradictions-location-location-location