Ok, ok, so maybe it's impossible to choose a single best place in the world to backpack but I'm making the case for the Sierra ***just for fun***. My reasons are as follows:

* MILLIONS of acres of protected wilderness ([Southern sierra is the largest area of unbroken wilderness in the US](https://wilderness.net/learn-about-wilderness/fast-facts/)). It would take multiple lifetimes to see it all. Need I say more?
* Incredible scenic beauty, from the Yosemite rim to the high peaks of the southern sierra. The white/gray granite of the mountains contrasting with the dark green of the forests, and the shimmering blue of the thousands of lakes is incredibly aesthetic. Some areas are genuinely jaw dropping in a way I have only experienced in a handful of other places.
* Unbeatable weather. It's beautiful and sunny most of the time from May-Oct.
* Incredible trail network, extremely well built and maintained trails from Tahoe to Whitney.
* Offtrail travel is extremely easy due to the open forested terrain and massive expanse of above treeline terrain. It feels like a playground.
* The challenge is there is you want it. Want intense cross country traverses? Endless summit objectives? Extremely remote areas where few dare to go? You name it, the Sierra has it.
* It is still possible to find solitude if you are experienced and willing to stray from the beaten path (which is easy as there is so much wilderness out there).
* The Sierra is biologically unique and interesting, endemic species (those that occur nowhere else in the world) can be observed by those interested in natural history.
* It's generally safe.

Downsides:

* Less charismatic wildlife than the rockies.
* Permits can be difficult to get at popular trailheads.

Sources: Just my opinion, I've backpacked all over the western US and South America.

  
Bonus: Curious if anyone knows where I took these photos.

The Sierra Nevada is the best place to backpack in the world