Where is The Lord of the Rings set?  I say it’s the Americas.  Here’s why:

1.  Pipeweed.  That’s tobacco, sure enough, and that’s a native American species.
   

   Tobacco

2.  Potatoes.  Same deal: the Americas.
   

   Potatoes

3. The Great River.  Nothing in Europe, and especially nothing in England, can compare with either the Mighty Mississippi or the Amazon.

The Mississippi River

Conclusion:  The Lord of the Rings, totally in the Americas.