How do I locate info on farms Numbered: 3790, 3792 & 3795

Where do I find a Farm Number index? There IS one, right?

Old papers were found in my father-in-law's files referencing Gas & Oil royalties he received over the years (small, but none the less...) from 3 family farms located in Eagle and Sardis Districts where the rights were passed down from his wife's grandparent's family. It looks like these royalties were derived from gas well heads, but it begs the question of just what is the status of the mineral rights at these farms.

I am not sure what you mean by a farm number index. Tracts of land are identified in WV by taxing District, Map No. and Parcel No. The numbers you have provided don't look like map and parcel numbers. Where did you get these numbers? They may be part of an API number that identifies wells.