Mostly around LA...

although that's a BIG area. Bonanza utilized many locations... if memory serves many more than The Big Valley. You can see the Vasquez Rocks in many episodes (You can google it). I have forgotten, (I once knew), where the opening titles shots were filmed but I believe those were in the Tahoe area... very near where the actual Ponderosa existed if not exactly there.

The Big Valley and Bonanza used basically the same areas. Most of those area have either been dozed under or encroached on to the extent that they are just tiny little islands surrounded by suburbia.

The Lone Ranger Rock.. when originally filmed, while not exactly in the 'boonies', was in open land... now homes nearly touch it.

Little House On The Prairie's location is still 'somewhat' secluded... but it won't be for long.

The two saddest of all, for me.... are 1) Culver City Studios (Mayberry and MANY other old sitcoms)... now an industrial complex.. nothing left of it at all except, I think, a very small landmark put up to remember it. And 2) Bedford Falls (It's A Wonderful Life). I'll include a Google Earth view of the location of Bedford Falls today. - JamesJM

This breaks my heart. Took me a long time to find Bedford Falls... one website to another to many forums and reading some old script PDF's. And sadly.. this is Bedford Falls today