Where was Jed from?
In the promo episode: the OK Oil Company has purchased the Bug Tussle property from the Clampetts for 25 million dollars.
I don't believe it was ever mentioned specifically where the Hillbillies lived, but I have some conclusions based on clues and tidbits from several episodes:
In one show, Jed and Pearl (Jethro's mother) go to the movies in Eureka Springs, Arkansas.
Jed and Pearl are said to live eight miles apart.
Jethro is reportedly from Bug Tussle.
The Clampetts once took a back road from Bug Tussle to Silver Dollar City, near Branson, Missouri, where they have friends.
From these facts, it can be concluded the clan lived in the southern Missouri Ozarks, near Bug Tussle.