Genesis 2:11 (ESV)

11 The name of the first is the Pishon. It is the one that flowed around the whole land of Havilah, where there is gold.

It is difficult to pinpoint the exact location of these rivers. The reason is that from Scripture and archaeology we cannot say with certainty where the Pishon and the Gihon Rivers were found. Another problem is that we cannot say with certainty where the land of Havilah may have been. It is clear that when this was written this land was known for its gold, which came from it.