"The region where they lived stretched from Mesha toward Sephar, in the eastern hill country." NIV translation
Mesha was an early form of the name of the modern city of Mecca. The descendants of Joktan would come to live in what we call Saudi Arabia.
"These are the sons of Shem by their clans and languages, in their territories and nations. These are the clans of Noah's sons, according to their lines of descent, within their nations. From these the nations spread out over the earth after the flood." NIV translation
In this overview of the root of the nations, we have also come to see the root of the strife that exists between the nations of today.
The division that we saw in the line of Shem continues even today.